Black Box Cable Box May 95 User Manual

MAY 1995  
ME758C-RJ11  
ME758C-RJ45  
ME759C-RJ11  
ME759C-RJ45  
Multi-Function LD Cards  
Power  
TD  
RD  
RTS  
CD  
Error  
est  
T
Analog  
Remote  
1
51  
1/E  
51  
CUSTOMER  
SUPPORT  
INFORMATION  
Order toll-free in the U.S.: Call 877-877-BBOX (outside U.S. call 724-746-5500)  
FREE technical support 24 hours a day, 7 days a week: Call 724-746-5500 or fax 724-746-0746  
Mailing address: Black Box Corporation, 1000 Park Drive, Lawrence, PA 15055-1018  
 
MULTI-FUNCTION LD CARD  
NORMAS OFICIALES MEXICANAS (NOM)  
ELECTRICAL SAFETY STATEMENT  
INSTRUCCIONES DE SEGURIDAD  
1. Todas las instrucciones de seguridad y operación deberán ser leídas antes de  
que el aparato eléctrico sea operado.  
2. Las instrucciones de seguridad y operación deberán ser guardadas para  
referencia futura.  
3. Todas las advertencias en el aparato eléctrico y en sus instrucciones de  
operación deben ser respetadas.  
4. Todas las instrucciones de operación y uso deben ser seguidas.  
5. El aparato eléctrico no deberá ser usado cerca del agua—por ejemplo, cerca  
de la tina de baño, lavabo, sótano mojado o cerca de una alberca, etc..  
6. El aparato eléctrico debe ser usado únicamente con carritos o pedestales que  
sean recomendados por el fabricante.  
7. El aparato eléctrico debe ser montado a la pared o al techo sólo como sea  
recomendado por el fabricante.  
8. Servicio—El usuario no debe intentar dar servicio al equipo eléctrico más allá  
a lo descrito en las instrucciones de operación. Todo otro servicio deberá ser  
referido a personal de servicio calificado.  
9. El aparato eléctrico debe ser situado de tal manera que su posición no  
interfiera su uso. La colocación del aparato eléctrico sobre una cama, sofá,  
alfombra o superficie similar puede bloquea la ventilación, no se debe colocar  
en libreros o gabinetes que impidan el flujo de aire por los orificios de  
ventilación.  
10. El equipo eléctrico deber ser situado fuera del alcance de fuentes de calor  
como radiadores, registros de calor, estufas u otros aparatos (incluyendo  
amplificadores) que producen calor.  
11. El aparato eléctrico deberá ser connectado a una fuente de poder sólo del  
tipo descrito en el instructivo de operación, o como se indique en el aparato.  
2
 
NOM STATEMENTS  
12. Precaución debe ser tomada de tal manera que la tierra fisica y la polarización  
del equipo no sea eliminada.  
13. Los cables de la fuente de poder deben ser guiados de tal manera que no  
sean pisados ni pellizcados por objetos colocados sobre o contra ellos,  
poniendo particular atención a los contactos y receptáculos donde salen del  
aparato.  
14. El equipo eléctrico debe ser limpiado únicamente de acuerdo a las  
recomendaciones del fabricante.  
15. En caso de existir, una antena externa deberá ser localizada lejos de las lineas  
de energia.  
16. El cable de corriente deberá ser desconectado del cuando el equipo no sea  
usado por un largo periodo de tiempo.  
17. Cuidado debe ser tomado de tal manera que objectos liquidos no sean  
derramados sobre la cubierta u orificios de ventilación.  
18. Servicio por personal calificado deberá ser provisto cuando:  
A: El cable de poder o el contacto ha sido dañado; u  
B: Objectos han caído o líquido ha sido derramado dentro del aparato; o  
C: El aparato ha sido expuesto a la lluvia; o  
D: El aparato parece no operar normalmente o muestra un cambio en su  
desempeño; o  
E: El aparato ha sido tirado o su cubierta ha sido dañada.  
3
 
MULTI-FUNCTION LD CARD  
Contents  
Chapter  
Page  
1. Specifications ............................................................................................. 5  
2. Introduction ............................................................................................... 8  
2.1 Overview .............................................................................................. 8  
2.2 Features ............................................................................................... 8  
3. Configuration ........................................................................................... 10  
3.1 Setting the Switches on the Main Module ....................................... 10  
3.2 Setting the Jumpers on the Interface Module ................................ 17  
4. Installation ................................................................................................ 22  
4.1 The MicroRacks: An Overview ......................................................... 22  
4.2 The MicroRacks’ Power Supply ....................................................... 23  
4.3 Installing the Multi-Function LD Card in the MicroRack .............. 24  
4.4 The RS-232 Serial Cables and Connectors ...................................... 25  
4.5 The Modem-to-Modem Line Cables and Connectors .................... 26  
4.6 Multipoint Applications .................................................................... 28  
5. Operation and Diagnostics ...................................................................... 29  
5.1 Status LEDs ........................................................................................ 29  
5.2 Diagnostic Testing Using the Error LED ........................................ 31  
5.3 Power-Up ........................................................................................... 32  
5.4 V.54 and V.52 Diagnostic Tests ........................................................ 33  
6. Troubleshooting ...................................................................................... 36  
6.1 Calling Your Supplier ....................................................................... 36  
6.2 Shipping and Packaging ................................................................... 36  
Appendix: Cable Recommendations ............................................................. 37  
4
 
CHAPTER 1: Specifications  
1. Specifications  
Hardware  
Required —  
Cards can be installed only in MicroRacks (see  
Section 4.1)  
Cable Required —  
For modem-to-modem line: Two- or four-wire  
unconditioned twisted-pair, 19 to 26 AWG (see  
the Appendix), pinned as shown in Section 4.5  
Compliance —  
Interfaces —  
FCC Part 15 Class A, DOC Class/MDC classe A  
Serial:  
ME758C models: EIA/TIA-561 (compatible with  
EIA RS-232 and ITU-TSS [CCITT] V.24);  
ME759C models: EIA RS-232/ITU-TSS V.24  
Line: Two- or four-wire telco;  
Internal: Card-edge for moduleMicroRack  
interconnection  
Protocol —  
Synchronous or asynchronous  
Clock Source —  
Internal, external (from DTE) or received (from  
other Card) (user-selectable)  
Data Format —  
Flow Control —  
Word length (including start bit, data bits, stop bits,  
and parity bit) must equal 8, 9, 10, or 11 bits (user-  
selectable)  
Transparent to all types of software (X-ON/X-OFF,  
robust X-ON/X-OFF, etc.) flow control; can be set  
to support hardware flow control  
Operating Mode — Two-wire half-duplex or four-wire full- or half-  
duplex (user-selectable)  
5
 
MULTI-FUNCTION LD CARD  
Data Rates —  
57.6, 38.4, 28.8, 19.2, 14.4, 9.6, 7.2, 4.8, 3.6, 2.4, or  
1.2 kbps (user-selectable)  
Maximum  
Distance —  
See the maximum distance chart in the Appendix  
Isolation —  
1500 volts RMS minimum using custom transformers  
Surge-Protection  
Method —  
Silicon Avalanche Diodes  
1 ps  
Surge-Response  
Time —  
Maximum Surge  
Protection —  
600 watts dissipated after 1 ms  
User Controls —  
(2) Front-panel toggle switches:  
Remote or (local) Analog loopback;  
511 or 511/E V.52 diagnostics;  
(3) 8-position DIP switches on main module:  
(1) for data rate, clock source, protocol, and carrier  
control;  
(1) for 2- or 4-wire operation, diagnostics, RTS/CTS  
delay, signaling-rate range, and word length;  
(1) for input impedance, point-to-point or  
multipoint operation, remote loopback-test  
initiation, and antistream control;  
(3) Frame-ground-connection jumpers on interface  
module:  
To Line Shield, DTE Shield (Protective Ground),  
and Signal Ground  
Indicators —  
(11) Front-panel LEDs:  
(1) each for Power, Test, Error;  
(2) each for TD, RD, RTS, and CD  
Diagnostics —  
Connectors —  
ITU-TSS V.54 remote digital and local analog  
loopbacks; ITU-TSS V.52 BERT testing  
On main module:  
All models:  
6
 
CHAPTER 1: Specifications  
(1) 50-position card-edge male (to MicroRack);  
On interface module:  
All models:  
(1) 50-position card-edge male (to MicroRack);  
ME758C-RJ11:  
(1) 6-pin RJ-11 female for modem-to-modem line,  
(1) DB25 female for modem-to-DTE line;  
ME758C-RJ45:  
(1) RJ-45 female for modem-to-modem line,  
(1) DB25 female for modem-to-DTE line;  
ME759C-RJ11:  
(1) 6-pin RJ-11 female for modem-to-modem line,  
(1) 10-pin RJ female for modem-to-DTE line;  
ME759C-RJ45:  
(1) RJ-45 female for modem-to-modem line,  
(1) 10-pin RJ female for modem-to-DTE line  
Power —  
Fuse —  
From MicroRack’s power supply (see Section 4.2):  
Input 120 VAC or 240 VAC (user-selectable);  
Output: 10 VAC;  
Consumption: 1.8 watts typical  
On MicroRack (see Section 4.2.2):  
400 mA when power supply is set to 120-VAC input;  
200 mA when power supply is set to 240-VAC input  
Temperature —  
Humidity —  
32 to 122˚F (0 to 50˚C)  
Up to 95% noncondensing  
Maximum  
Altitude —  
15,000 ft. (4572 m)  
Size —  
Main (front) module: 3.1"H x 1"W x 5.4"D  
(7.9 x 2.5 x 13.7 cm);  
Interface (rear) module: 3.5"H x 1"W x 2.9"D  
(8.9 x 2.5 x 7.4 cm)  
Weight —  
Total for main and interface modules: 0.2 lb. (0.1 kg)  
7
 
MULTI-FUNCTION LD CARD  
2. Introduction  
2.1 Overview  
The Multi-Function LD Card is a short-range modem on a dual rack card (it  
has a main [front] module and an interface [rear] module). The Card  
operates across two wires (half-duplex) or four wires (full- or half-duplex),  
communicating synchronously or asynchronously, up to a maximum range of  
20 miles (32.2 km). You can set the Card to any of twelve data rates from 1.2  
to 57.6 kbps. Local and remote modems on Multi-Function LD Cards always  
communicate with each other synchronously. When connected to an  
asynchronous RS-232 device, the Card performs synchronousasynchronous  
conversion.  
The Card has several features that enhance its overall performance,  
including automatic equalization, automatic gain control, an antistreaming  
timer, transformer isolation, and Silicon Avalanche Diode surge protection.  
The Card also has strong diagnostics: It features V.52-compliant bit-error-rate  
(BERT) pattern tests and two V.54 test modes. With the Card’s 11 easy-to-read  
front-panel LEDs, you can easily monitor the status of data transmission and  
diagnostic testing.  
The Multi-Function LD Card is fabricated using the latest surface-mount  
technology, so you get high-quality short-range-modem performance on a  
convenient rack card. The Card is available with either DB25 or 10-pin RJ-style  
serial-interface connectors, and either RJ-11 or RJ-45 line-interface  
connectors, on its interface (rear) module. It fills one function-card slot in  
our MicroRacks (RM202, RM204, RM208, or RM216).  
2.2 Features  
• Convenient rack-card design  
• Synchronous or asynchronous communication  
• Data rates up to 57.6 kbps, distances up to 20 miles (32.2 km)  
• 2-wire/half-duplex or 4-wire/full- or half-duplex operation  
• Point-to-point or multipoint operation  
8
 
CHAPTER 2: Introduction  
• Internal, external, or received loopback clocking  
• Hardware or software flow control  
• Automatic equalization and gain control  
• Anti-streaming timer  
• Built-in transformer isolation and high-speed surge protection  
• V.52 and V.54 test modes  
• Eleven LED indicators show you status at a glance  
• Error LED lights when Card detects broken or inferior cable  
9
 
MULTI-FUNCTION LD CARD  
This chapter describes the locations and posssible settings of the Multi-  
Function LD Card’s configuration controls, and provides detailed instructions  
for setting them. Section 3.1 tells you about the three 8-position DIP switches  
on the Card’s main (front) module. Section 3.2 tells you about the three  
jumpers (“straps”) on the Card’s interface (rear) module. Once you’ve  
configured the Multi-Function LD Card, it is designed to operate  
transparently, without needing to be frequently reconfigured. Just set it and  
forget it!  
3.1 Setting the Switches on the Main Module  
3.1.1 WHERE THE SWITCHES ARE  
The Multi-Function LD Card has three 8-position DIP switches—S1, S2, and  
S3—mounted on the circuit board of its main (front) module, as shown in  
Figure 3-1 below. These configuration switches allow you to select data rates,  
clocking methods, V.52 and V.54 tests, word lengths, extended signaling rates,  
sync or async protocol, 2- or 4-wire operation, antistream control, and input  
impedance. As shown in Figure 3-2 on the next page, the “ON” and “OFF”  
points are the same for all of the switch positions.  
S1  
S2  
S3  
(on other  
side of  
board)  
Figure 3-1. The main-module switches.  
10  
 
CHAPTER 3: Configuration  
ON  
ON  
1
2
3
4
5
6 7 8  
OFF  
Figure 3-2. The ON and OFF settings of the DIP switches.  
3.1.2 CONFIGURATION SWITCH “S1”  
Use the individual positions on DIP switch S1 to set data rate, clock source,  
sync vs. async protocol, and carrier-control method. The factory-default  
settings are summarized in Table 3-1 below.  
Table 3-1. Switch S1 Summary  
Position Function  
Default Setting  
S1-1  
S1-2  
S1-3  
S1-4  
Data Rate  
Data Rate  
Data Rate  
Data Rate  
On  
Off  
Off  
On  
9600 bps  
S1-5  
S1-6  
Clock Source  
Clock Source  
On  
On  
Internal  
S1-7  
S1-8  
Protocol  
On  
Off  
Asynchronous  
Constantly ON  
Carrier Control  
11  
 
MULTI-FUNCTION LD CARD  
S1 Positions 1 through 4: Data-Rate Setting  
Set positions 1 through 4 of switch S1 to determine the data rate (valid for  
both synchronous and asynchronous protocols) of the Multi-Function LD  
Card.  
S1-1  
On  
Off  
On  
Off  
On  
Off  
On  
Off  
On  
Off  
On  
Off  
S1-2  
On  
On  
Off  
Off  
On  
On  
Off  
Off  
On  
On  
On  
On  
S1-3  
On  
On  
On  
On  
Off  
Off  
Off  
Off  
On  
On  
Off  
Off  
S1-4  
On  
On  
On  
On  
On  
On  
On  
On  
Off  
Off  
Off  
Off  
Data Rate  
1.2 kbps  
1.8 kbps  
2.4 kbps  
3.6 kbps  
4.8 kbps  
7.2 kbps  
9.6 kbps (default)  
14.4 kbps  
19.2 kbps  
28.8 kbps  
38.4 kbps  
57.6 kbps  
S1 Positions 5 and 6: Clock Source  
Set positions 5 and 6 of switch S1 to determine which transmit-clock source  
the Multi-Function LD Card uses.  
S1-5  
On  
Off  
On  
S1-6  
On  
On  
Off  
Clock Source  
Internal transmit clock (default)  
Receive-recover clock  
External transmit clock  
S1 Position 7: Protocol  
Set position 7 of switch S1 to determine whether the Multi-Function LD Card  
operates synchronously or asynchronously.  
S1-7  
On  
Off  
Protocol  
Asynchronous (default)  
Synchronous  
12  
 
CHAPTER 3: Configuration  
S1 Position 8: Carrier-Control Method  
Set position 8 of switch S1 to determine whether the carrier is “constantly on”  
or “controlled by RTS.” In the “controlled by RTS” setting, the Switch can  
support switched-carrier, multipoint, or hardware flow-control applications.  
S1-8  
Off  
On  
Carrier  
Constantly ON (default)  
Controlled by RTS  
3.1.3 CONFIGURATION SWITCH “S2”  
Use the individual positions on DIP switch S2 to set word length, signaling-  
rate range, RTS/CTS delay, or 2- or 4-wire operation, as well as to control  
diagnostic testing. The factory-default settings are summarized in Table 3-2  
below.  
Table 3-2. Switch S2 Summary  
Position Function  
Default Setting  
S2-1  
S2-2  
S2-3  
Not Used  
N/A  
2-Wire/4-Wire  
V.52, V.54 Tests  
Off  
Off  
4-Wire  
Normal Operation  
S2-4  
S2-5  
RTS/CTS Delay  
RTS/CTS Delay  
On  
On  
7 ms  
S2-6  
Signaling-Rate Range  
On  
-2.5 to +1%  
10 bits  
S2-7  
S2-8  
Word Length  
Word Length  
Off  
Off  
S2 Position 2: 2-Wire vs. 4-Wire Operation  
Set position 2 of switch S2 to determine whether the Multi-Function LD Card  
operates in 2-wire or 4-wire mode.  
S2-2  
Off  
On  
Operation  
4-wire (full- or half-duplex) (default)  
2-wire (half-duplex only)  
13  
 
MULTI-FUNCTION LD CARD  
S2 Position 3: V.52 and V.54 Diagnostic Testing  
To reset the V.54 circuit, turn switch S2 position 3 ON, then back OFF.  
S2-3  
Off  
On  
Test Mode  
Normal Operation (default)  
Test Disabled  
S2 Positions 4 and 5: RTS/CTS Delay  
Set positions 4 and 5 of switch S2 to determine the amount of time the Multi-  
Function LD Card waits after it “sees” RTS before it sends CTS. Possible  
settings are no delay, 7 ms, or 53 ms.  
S2-4  
On  
On  
Off  
Off  
S2-5  
On  
Off  
On  
Off  
RTS/CTS Delay  
7 ms (default)  
53 ms  
No delay  
No delay  
S2-6: Signaling-Rate Range  
Set position 6 of switch S2 to determine the degree of asynchronous data-rate  
fluctuation that the Multi-Function LD Card will accept (that is, how much  
variance from a given frequency level the Card will tolerate).  
S2-6  
Off  
On  
Signaling-Rate Range  
-2.5% to +1% (default)  
-2.5% to +2.3%  
S2-7 and S2-8: Word Length  
Set positions 7 and 8 of switch S2 to determine the word length that the Multi-  
Function LD Card will expect for synchronous or asynchronous data. For  
example, if you are using the most common data format (1 start bit,  
8 data bits, 1 stop bit, and no parity), you would use the factory-default word-  
length setting (10 bits).  
S2-7  
On  
On  
Off  
Off  
S2-8  
Off  
On  
Off  
On  
Word Length  
8 bits  
9 bits  
10 bits (default)  
11 bits  
14  
 
CHAPTER 3: Configuration  
3.1.4 CONFIGURATION SWITCH “S3”  
Use the individual positions on DIP switch S3 to set antistream control,  
receive (input) impedance, and point-to-point/multipoint, as well as to  
enable or disable local and remote loopbacks. The factory-default settings are  
summarized in Table 3-3 below.  
Table 3-3. Switch S3 Summary  
Position Function  
Default Setting  
S2-1  
S2-2  
Input Impedance  
Input Impedance  
On  
200 ohms  
Off  
N/A  
On  
Off  
S2-3  
S2-4  
S2-5  
S2-6  
Reserved  
Pt.-to-Pt./Multipoint  
DTE Local Loopback  
Point-to-Point  
Disabled  
DTE Remote Loopback Off  
Disabled  
S2-7  
S2-8  
Antistream Control  
Antistream Control  
Off  
Off  
Disabled  
S3-1 and S3-2: Input Impedance  
Set positions 1 and 2 of switch S3 to determine the Multi-Function LD Card’s  
input impedance.  
Choose the optimum impedance setting for your application. In long-  
distance applications, the impedance of the cable must match the impedance  
of the load (or resistor) of the Multi-Function LD Card: Thicker-gauge cables  
require a lower ohm setting, while thinner-gauge cables require a higher ohm  
setting. Also, higher data rates call for a lower ohm setting, and lower data  
rates dictate a higher ohm setting. Table 3-4 below lists our recommendations  
for setting this switch.  
S3-1  
On  
On  
Off  
Off  
S3-2  
On  
Off  
On  
Off  
Input Impedance  
130 ohms  
200 ohms (default)  
320 ohms  
High (minimum 2000 ohms)  
15  
 
MULTI-FUNCTION LD CARD  
Table 3-4. Recommended Impedance Settings  
Cable  
Data Rates in kbps  
Gauge  
1.2 1.8 2.4 3.6 4.8 7.2 9.6 14.4 19.2 28.8 38.4 57.6  
19  
22  
24  
26  
320 320 200 200 200 200 200 130 130 130 130 130  
320 320 320 200 200 200 200 200 130 130 130 130  
320 320 320 320 200 200 200 200 200 130 130 130  
320 320 320 320 320 200 200 200 200 200 130 130  
S3-4: Mode Selection  
Set position 4 of switch S3 to determine whether the Multi-Function LD Card  
operates in point-to-point or multipoint mode.  
S3-4  
On  
Off  
Operation  
Point-to-point (also multipoint as the “master”) (default)  
Multipoint (as a “slave”)  
S3-5: DTE RS-232 Initiation of Local Loopback Test  
Set position 5 of switch S3 to determine whether or not the attached DTE can  
initiate the Multi-Function LD Card’s local analog loopback test by raising the  
Local Loopback (LL) signal on Pin 18 of the RS-232 interface.  
S3-5  
On  
Off  
DTE Initiation of Local Loopback  
Enabled  
Disabled (default)  
S3-6: DTE RS-232 Initiation of Remote Loopback Test  
Set position 6 of switch S3 to determine whether or not the Multi-Function  
LD Card’s remote analog loopback test can be initiated by raising the Remote  
Loopback (RL) signal on Pin 21 of the RS-232 interface.  
S3-6  
On  
Off  
DTE Initiation of Remote Loopback  
Enabled  
Disabled (default)  
16  
 
CHAPTER 3: Configuration  
S3-7 and S3-8: Antistream Control  
Set positions 7 and 8 of switch S3 to determine the timeout period for the  
Multi-Function LD Card’s antistream-control timer, or to disable the timer  
entirely.  
S3-7  
Off  
Off  
On  
On  
S3-8  
Off  
On  
Off  
On  
Setting  
Disabled (default)  
12.5 seconds  
50 seconds  
12.5 seconds  
3.2 Setting the Jumpers on the Interface Module  
3.2.1 THE INTERFACE-MODULE OPTIONS  
The Multi-Function LD Card has four interface-module options:  
• The ME758C-RJ11 has a DB25 connector for an RS-232 serial port and an  
RJ-11 modem-to-modem port.  
• The ME758C-RJ45 has a DB25 connector for an RS-232 serial port and an  
RJ-45 modem-to-modem port.  
• The ME759C-RJ11 has a 10-pin RJ-style connector for an RS-232  
compatible serial port and an RJ-11 modem-to-modem port.  
• The ME759C-RJ45 has a 10-pin RJ-style connector for an RS-232  
compatible serial port and an RJ-45 modem-to-modem port.  
17  
 
MULTI-FUNCTION LD CARD  
Figure 3-3, below, shows the rear panels of each of these interface modules.  
ME758C-RJ45  
ME759C-RJ11  
ME758C-RJ11  
ME759C-RJ45  
Line: RJ-45  
Line: RJ-45  
Line: RJ-11  
Line: RJ-11  
Serial: DB25  
Serial: DB25  
Serial: 10-Pin RJ Serial: 10-Pin RJ  
Figure 3-3. The four interface modules.  
Before you install the Card, you should examine the interface module you  
have selected and make sure that it is configured for your application. Each  
interface module has three jumpers on its circuit board, as described in the  
following sections.  
3.2.2 THE CONFIGURATION JUMPERS ILLUSTRATED  
Figure 3-4, below, shows the possible settings of the Multi-Function LD Card’s  
jumpers. Each jumper can be either on pegs 1 and 2, as shown at left, or on  
pegs 2 and 3, as shown at right.  
1
2
3
1
2
3
Figure 3-4. The possible jumper settings.  
18  
 
CHAPTER 3: Configuration  
3.2.3 WHERE THE JUMPERS ARE  
Figure 3-5, below, shows the locations of the jumpers on the interface  
modules (the locations are the same for both the -RJ11 and -RJ45 models).  
These jumpers determine various grounding and signal characteristics for the  
serial and modem-to-modem lines.  
JB2  
JB3  
(peg 1 on left)  
(peg 1 on top)  
ME758C interface  
module  
JB4  
(peg 1 on left)  
JB2  
(peg 1 on top)  
JB3  
ME759C interface  
module  
(peg 1 on top)  
JB4  
(peg 1 on left)  
Figure 3-5. The jumper locations.  
19  
 
MULTI-FUNCTION LD CARD  
Table 3-5, below, provides a summary of the functions of these jumpers. The  
functions are described in more detail afterward.  
Table 3-5. Summary of Interface-Module Jumper Functions  
Jumper Function  
Pos. 1 & 2  
Pos. 2 & 3  
JB2  
JB3  
JB4  
Line Shield and FGND  
Connected N/C*  
PGND (DTE Pin 1) and FGND Connected N/C*  
SGND and FGND  
Connected N/C*  
*factory-default settings  
Line Interface: Line Shield Connection to Frame Ground (JB2)  
This jumper applies to the line interface. When this jumper is in positions 1  
and 2, it links RJ-11 Pins 1 and 6 or RJ-45 Pins 2 and 7 on the corresponding  
line to the interface module’s frame ground. (If you are using shielded  
twisted-pair cable, the shield can be connected to these pins.) In positions 2  
and 3, RJ-11 Pins 1 and 6 or RJ-45 Pins 2 and 7 remain connected to each  
other, but are disconnected (“lifted”) from frame ground.  
JB2  
Positions 1 and 2 = Line Shield and FGND Connected  
Positions 2 and 3 = Line Shield and FGND Not Connected (default)  
CAUTION!  
If you connect shield to frame ground, make sure that RJ-11 Pins 1 and 6  
or RJ-45 Pins 2 and 7, as well as the cable shield, are connected to  
ground at one end of the cable only. Connecting them at both ends of the  
cable will defeat the transformer isolation and will leave your system  
open to damage from ground loops.  
20  
 
CHAPTER 3: Configuration  
Serial Interface: DTE Shield (Pin 1) Connection to Frame Ground (JB3)  
This jumper applies to the serial interface. In position 1 and 2, this jumper  
links the Protective Ground (PGND) or “DTE Shield” lead (DB25 Pin 1 or 10-  
pin RJ Pins 1 and 10) of the RS-232 line to the interface module’s frame  
ground (FGND). When this jumper is in positions 2 and 3, the RS-232  
Protective Ground on DB25 Pin 1 or RJ-45 Pins 1 and 10 is disconnected  
(“lifted”) from frame ground.  
JB5  
Positions 1 and 2 = PGND and FGND Connected  
Positions 2 and 3 = PGND and FGND Not Connected (default)  
Serial Interface: Signal Ground and Frame Ground (JB4)  
This jumper also applies to the serial interface. In position 1 and 2, this  
jumper links the Signal Ground (SGND) lead (DB25 Pin 7 or 10-pin RJ  
Pin 5) of the RS-232 line to the interface module’s frame ground (FGND).  
When this jumper is in positions 2 and 3, RS-232 Signal Ground on DB25 Pin  
7 or 10-pin RJ Pin 5 is disconnected (“lifted”) from frame ground.  
JB5  
Positions 1 and 2 = SGND and FGND Connected  
Positions 2 and 3 = SGND and FGND Not Connected (default)  
21  
 
MULTI-FUNCTION LD CARD  
4. Installation  
This chapter describes the functions of the MicroRacks, tells how to install the  
front and rear modules of the Multi-Function LD Cards in them, and provides  
diagrams for wiring the interface connections correctly.  
4.1 The MicroRacks: An Overview  
Multi-Function LD Cards are designed to be installed in our MicroRacks  
(product codes RM202 for the 2-card models, RM204 for the 4-card models,  
RM208 for the 8-card models, and RM216 for the 16-card models). You will  
install Multi-Function LD Cards in any MicroRack the same way.  
As an example of these products, the MicroRack 16, shown in Figure 4-1  
below, features sixteen slots for short-range modem cards, plus its own power  
supply. Measuring only 3.5" (8.9 cm) high, the MicroRack 16 is designed to  
occupy only 2U in a 19" rack. Sturdy front handles allow the MicroRack 16 to  
be extracted and transported conveniently.  
Figure 4-1. The MicroRack 16 (shown with fifteen  
Multi-Function LD Cards installed).  
22  
 
CHAPTER 4: Installation  
4.2 The MicroRacks’ Power Supply  
The power supply included with the MicroRacks uses the same mid-plane  
architecture as the line-driver cards. Slide the front module of the power  
supply into the MicroRack from the front, and slide the rear module in from  
the rear. The two modules plug into one another in the middle of the rack.  
Secure the front module with thumbscrews and the rear module with  
conventional metal screws; these screws and thumbscrews come with the rack.  
4.2.1 SWITCHING THE POWER SUPPLY ON AND OFF  
The MicroRack’s power switch is located on the power supply’s front panel.  
When the MicroRack is plugged in and switched on, the power supply will  
light the red LED on its front panel. Since the MicroRack is a “hot-swappable”  
rack, you don’t have to install any cards before switching on the power supply. Also,  
the power supply may be switched off at any time without harming the  
installed cards, and you can install or remove cards without turning off the  
power supply. However, you should always unplug the power cord before  
removing, replacing, or switching the power supply or its fuses.  
4.2.2 REPLACING THE POWER SUPPLYS FUSE  
The MicroRack’s power supply uses a 400-mA fuse for 120-VAC circuits, and a  
200-mA fuse for 240-VAC circuits. The fuse compartment is located just below  
the AC socket on the power supply’s rear module. To replace the fuse, follow  
these steps:  
1. Making sure the rack is turned off and unplugged, use a small screw-  
driver to pop the compartment open: It will slide open like a drawer.  
2. Notice that there are two fuses in the compartment: The rear fuse is  
“active,” and the front fuse is the “spare.”  
3. If the active fuse appears to be blown, remove it from the clips and  
replace it with the spare from the front of the compartment. Note the  
size and rating of the blown fuse before discarding it.  
®
4. Order a new replacement fuse. Both the 400-mA fuses (Littelfuse  
239.400 or equivalent) and the 200-mA fuses (Littelfuse 239.200 or  
equivalent) measure 5 x 20 mm.  
CAUTION!  
For continued protection against the risk of fire, replace blown fuses  
only with fuses of the same type and rating.  
23  
 
MULTI-FUNCTION LD CARD  
4.2.3 SWITCHING THE POWER SUPPLY BETWEEN 120 AND 240 VOLTS  
Although the MicroRack is shipped from the factory with a customer-specified  
power-supply configuration, you may change the configuration yourself.  
Follow these steps to switch the configuration of the power supply between  
120 VAC and 240 VAC:  
1. Making sure the rack is turned off and unplugged, remove the power  
supply’s front module and locate the two-position switch (labeled either  
“110/220” or “115/230”) near the back of the card. Slide the switch to  
the setting corresponding to your desired voltage.  
2. Replace the existing fuses with fuses of the correct type (see step 4 of  
Section 4.2.2).  
3. If necessary, replace the power-supply cord with a country-specific cord.  
(For certain countries, your supplier might be able to give you a special  
quote on country-specific cords.) Plug the cord back in.  
4.3 Installing the Multi-Function LD Card in the MicroRack  
The Multi-Function LD Card is made up of a main (front) module and an  
interface (rear) module. The two cards meet inside the rack chassis; their  
mating 50-pin card-edge connectors plug into each other. Use these steps to  
install each Multi-Function LD Card into a MicroRack:  
1. Slide the rear module into the back of the MicroRack on the metal rails.  
2. Secure the rear module using the included metal screws.  
3. Slide the front module into the front of the chassis. It should meet the  
rear module when it is almost completely in the chassis.  
4. Push the front module gently into the card-edge receptacle of the rear  
module. It should “click” into place.  
5. Secure the front module using the thumbscrews.  
NOTE  
Since the MicroRacks allow “hot swapping” of cards, it is not necessary to  
power down the rack when you install or remove a Multi-Function LD  
Card.  
24  
 
CHAPTER 4: Installation  
4.4 The RS-232 Serial Cables and Connectors  
The Multi-Function LD Card’s RS-232 port is always the lower port on its  
interface module. On ME758C models it is a standard DB25 connector  
(pinout shown in Table 4-1 below, top). On ME759C models it is a 10-pin  
female RJ-style connector (compatible with regular male RJ-45 cable  
connectors), pinned according to a modified version of the EIA/TIA-561  
standard, as shown in Table 4-2 below (bottom).  
Table 4-1. Pinout of the RS-232 Interface  
DIRECTION  
STANDARD RS-232/V.24 DCE PINNING  
DIRECTION  
1 Protective Ground (PGND)  
2 Transmit Data (TD)  
3 Receive Data (RD)  
To Card  
From Card  
To Card  
From Card  
Transmit Clock DCE (TCC) 15  
4 Request to Send (RTS)  
5 Clear to Send (CTS)  
6 Data Set Ready (DSR)  
7 Signal Ground (SGND)  
From Card  
To Card  
Receive Clock DCE (RCC) 17  
Local Loopback (LL) 18  
From Card  
From Card  
To Card  
To Card  
Data Terminal Ready (DTR) 20  
Remote Loopback (RL) 21  
To Card  
Transmit Clock DTE (TCT) 24  
Test Mode (TM) 25  
From Card  
Table 4-2. Pinout of the 10-Pin RJ Interface  
Pin  
ITU-TSS  
Signal Name/Description  
Number  
V.24  
Circuit  
0 0 0 0 0 0 0 0 0 1  
1 2 3 4 5 6 7 8 9 0  
1
2
N/A  
Not Used  
107  
DCE Ready (DCR [DSR])  
Received Line Signal Detector (RLSD [CD])  
DTE Ready (DTR)  
3
109  
4
108/2  
102  
5
Signal Common (SCOM [SGND])  
Receive Data (RD)  
6
104  
7
103  
Transmitted Data (TD)  
8
106  
Clear to Send (CTS)  
9
105 or 133  
N/A  
Request to Send (RTS) or Ready for Receiving (RR)  
Not Used  
10  
Pins 3 through 9 correspond to Pins 2 through 8 of the EIA/TIA-561 non-synchronous interface standard.  
Pin 2 corresponds to Pin 1 of the EIA/TIA TSB-25 preliminary interface standard.  
25  
 
MULTI-FUNCTION LD CARD  
The Multi-Function LD Card is wired as a DCE (Data Communications  
Equipment) device. Therefore, it would normally be connected to a DTE  
(Data Terminal Equipment) RS-232 device. You might need to run a special  
cable or use a special adapter if the serial port of the RS-232 device you want  
to attach is not the same type of connector as the one on your Card. Even if  
the serial ports on the Card and the DTE are both RJ-45 connectors, you  
might still need to use a specially pinned cable. Call your supplier for  
technical support with these issues, or if you want to attach a DCE device to  
the Card.  
4.5 The Modem-to-Modem Line Cables and Connectors  
The Multi-Function LD Card’s line port is always the upper port on its  
interface module. It is a 6-pin RJ-11 connector on the -RJ11 models or an  
8-pin RJ-45 connector on the -RJ45 models, pinned for a standard telco-wiring  
environment, as shown in Table 4-3 and Figure 4-2 on the next page.  
The Multi-Function LD Card operates half-duplex over two wires (one  
twisted pair) or full- or half-duplex over four wires (two twisted pairs). In all  
applications, the twisted-pair wire must be 26 AWG or thicker, unconditioned,  
dry, and metallic. Both shielded and unshielded cable yield favorable results.  
NOTE  
The Multi-Function LD Card can only communicate in a closed data  
circuit with another Multi-Function LD Card. It will not work with dialup  
analog circuits, such as those used with standard modems. For further  
information about acceptable wire grades, refer to the recommendations  
in the Appendix.  
The modem-to-modem cable connection must be specially cross-pinned, as  
shown in Table 4-3 and Figure 4-2 on the next page. If your cabling includes  
punchdown blocks, you can easily do the cross-pinning at a punchdown block.  
If you will be running cable directly between two Multi-Function LD Cards,  
you can get a custom cable from your supplier as a special quote, or you can  
use regular straight-through-pinned cable and repin one of the RJ connectors  
(that is, rearrange the wiring connections between the terminal block and the  
actual contacts). You might need special crimping tools or new connectors;  
call your supplier for these items, or for technical support if you have  
difficulty.  
26  
 
CHAPTER 4: Installation  
Table 4-3. Line-Cable Pinouts  
RJ-11 (Four-Wire)  
SIGNAL  
PIN#  
COLOR*  
COLOR*  
PIN#  
SIGNAL  
GND**  
RCV–†  
XMT+  
XMT–  
RCV+  
GND**  
1
2
3
4
5
6
Blue..................................................White  
Yellow ..............................................Red  
Green...............................................Black  
Red ..................................................Yellow  
Black................................................Green  
White................................................Blue  
6
4
5
2
3
1
GND**  
XMT–  
RCV+  
RCV–  
XMT+  
GND**  
RJ-45 (Four-Wire)  
SIGNAL  
PIN#  
COLOR*  
COLOR*  
PIN#  
SIGNAL  
GND**  
RCV–†  
XMT+  
XMT–  
RCV+  
GND**  
2
3
4
5
6
7
Orange.............................................Brown  
Black................................................Green  
Red ..................................................Yellow  
Green...............................................Black  
Yellow ..............................................Red  
Brown...............................................Orange  
7
5
6
3
4
2
GND**  
XMT–  
RCV+  
RCV–  
XMT+  
GND**  
RJ-11 (Two-Wire)  
SIGNAL  
PIN#  
COLOR*  
COLOR*  
PIN#  
SIGNAL  
XMT+†  
XMT–  
3
4
Green...............................................Green  
Red ..................................................Red  
3
4
XMT+  
XMT–  
RJ-45 (Two-Wire)  
SIGNAL  
PIN#  
COLOR*  
COLOR*  
PIN#  
SIGNAL  
XMT+†  
XMT–  
4
5
Red ..................................................Red  
Green...............................................Green  
4
5
XMT+  
XMT–  
*Standard color codes—wire colors in your cable might be different  
**Connection to ground is optional  
†The Multi-Function LD Card is not sensitive to polarity  
1 – Blue  
1 – Blue  
2 – Orange  
3 – Black  
4 – Red  
5 – Green  
6 – Yellow  
7 – Brown  
8 – Slate  
2 – Yellow  
3 – Green  
4 – Red  
5 – Black  
6 – White  
®
Figure 4-2. AT&T standard modular color codes.  
27  
 
MULTI-FUNCTION LD CARD  
4.6 Multipoint Applications  
The Multi-Function LD Card supports multipoint applications using  
equipment arranged in a star topology. Maximum distance between the units  
will vary based on the number of drops, data rate, wire gauge, etc. Call your  
supplier’s technical support for distance estimates more specific to your  
application. Figures 4-3 and 4-4 below show how to wire two-pair and one-pair  
cables respectively for a Multi-Function LD Card star network.  
HOST  
FIRST SLAVE  
SECOND SLAVE  
XMT  
RCV  
RCV  
RCV  
XMT  
XMT  
XMT  
RCV  
RCV  
RCV  
XMT  
XMT  
Figure 4-3. Two-pair star wiring for host and slave Cards.  
HOST  
FIRST SLAVE  
SECOND SLAVE  
XMT  
XMT  
XMT  
XMT  
XMT  
XMT  
Figure 4-4. Single-pair star wiring for host and slave Cards.  
28  
 
CHAPTER 5: Operation and Diagnostics  
5. Operation and Diagnostics  
Once you have configured each Multi-Function LD Card and connected the  
cables, you are ready to operate the units. This chapter describes the Card’s  
LEDs, the power-up procedure, and diagnostic testing.  
5.1 Status LEDs  
The Multi-Function LD Card features 11 front-panel status LEDs (shown in  
Figure 5-1 below) that indicate the condition of the modem and the  
communication link.  
Model 1080RC  
Power  
TD  
RD  
RTS  
CD  
Test  
Error  
Analog  
Remote  
511/E  
511  
Figure 5-1. The Card’s front panel.  
5.1.1 THE TD AND RD INDICATORS  
The TD and RD indicators (one red and one green LED for each signal)  
blink when data activity occurs: The red LEDs indicate a low RS-232 logic  
level, while the green LEDs indicate a high RS-232 logic level. Also, since RS-  
232 devices idle in a low state, the red LED will be steadily lit if the  
connections are correct and the RS-232 device is in an idle state.  
29  
 
MULTI-FUNCTION LD CARD  
5.1.2 THE RTS AND CD INDICATORS  
The RTS and CD indicators (again, one red and one green LED for each  
signal) function much like the TD and RD LEDs: The red LEDs light for a  
“low” signal, while the green LEDs light for a “high” signal. The RTS LEDs  
light for an incoming RTS signal on the RS-232 side (DB25 Pin 4 or 10-pin RJ  
Pin 9). The CD LEDs light for an incoming signal on the line side and the  
resulting output signal on the RS-232 side (DB25 Pin 8 or 10-pin RJ  
Pin 3).  
5.1.3 THE POWER INDICATOR  
The green Power LED lights to indicate that the Card is receiving power.  
5.1.4 THE TEST INDICATOR  
The green Test LED lights to indicate that V.52 or V.54 tests are running.  
5.1.5 THE ERROR INDICATOR  
The red Error LED has three functions:  
A. When the Card is in test mode (green Test LED is lit), the Error LED  
glows red when bit errors occur.  
B. When the Card is not in test mode (green Test LEDis dark), the Error  
LED is used to indicate an RTS streaming condition (see Section 5.2.2).  
C. The Error LED can also indicate line-quality problems (see  
Section 5.2.1) such as:  
1. The improper use of “flat satin” (non-twisted-pair) cable, or low-  
quality twisted-pair cable, to connect the modems.  
2. One or more broken wires in the 4-wire twisted-pair cable.  
4. Broken or corroded connectors.  
30  
 
CHAPTER 5: Operation and Diagnostics  
5.2 Diagnostic Testing Using the Error LED  
5.2.1 TESTING CABLE QUALITY  
NOTE  
The Error LED’s circuitry is designed to detect line quality across 4-wire  
twisted-pair cable only, and might not function properly with 2-wire  
cable.  
If there is any question as to the quality of your line, we recommend the  
following test:  
1. Disconnect both local and remote modems from their attached RS-232  
DTE devices. Make sure the red TD, RD, and RTS LEDs are all lit.  
2. Set the input impedance of both modems to 200 ohms by setting switch  
S3 position 1 “On” and S3 position 2 “Off.”  
3. Set the data rate on both modems to 9.6 kbps by setting switch S1  
position 1 “On,” S1 position 2 “Off,” S1 position 3 “Off,” and S1 position  
4 “On.”  
4. On the local modem, set carrier control for “Constantly on” by setting  
switch S1 position 8 “Off.”  
5. On the remote modem, set carrier control to “Controlled by RTS” by  
setting switch S1 position 8 to “On.”  
6. Move both front-panel toggle switches to the center (neutral) position.  
(The Test LED should not light.)  
7. Connect both modems to the 4-wire twisted-pair cable to be tested. (See  
Section 4.5 for pinouts and guidelines for this type of cable.)  
8. Here’s how to interpret the results:  
A. If the quality of the line is good, neither modem’s Error LED will  
light. The local modem’s red CD LED will light, and the remote  
modem’s green CD LED will light.  
B. If there is flat satin cable in the line somewhere between the modems,  
the local modem’s Error LED and green CD LED will both light. On  
the remote modem, the remote modem’s green CD LED will light,  
but the Error LED will stay dark.  
31  
 
MULTI-FUNCTION LD CARD  
NOTE  
We cannot guarantee that the Card will accurately detect small pieces of  
flat satin cable in the line if they are farther than 1500 ft. (457.2 m) from  
the local modem.  
C. If one wire among the four twisted-pair wires is broken, the Error  
LED and the green CD LED will both light on at least one of the  
modems.  
5.2.2 DETECTING STREAMING ERRORS  
When the Multi-Function LD Card is not in test mode (its green Test LED is  
dark), the front-panel Error LED can also indicate streaming errors. When  
the Card’s antistreaming circuitry is enabled (one or both of switch S3  
positions 7 and 8 set to “On”), the RTS signal from the attached DTE is timer-  
controlled. The timer begins to count down when the DTE raises RTS. If RTS  
remains high for longer than the preset timeout period, the antistream circuit  
will force RTS low. The Error LED will light, indicating a streaming condition  
(RTS continually on). This feature prevents a malfunctioning terminal from  
tying up a computer port in a multidrop or polling environment.  
When the DTE drops RTS, the antistreaming timer is automatically reset  
and the Error LED goes dark. The timeout period is user-selectable for 12.5  
or 50 seconds. See Section 3.1.4.  
5.3 Power-Up  
There is no power switch on the Multi-Function LD Card: Power is  
automatically applied to the Card whenever—and for as long as—its card-  
edge connector is plugged into the MicroRack’s mid-plane socket and the  
MicroRack’s power supply is turned on.  
NOTE  
The Multi-Function LD Card is a “hot-swappable” card—it will not be  
damaged by plugging it in or removing it while the rack is powered up.  
32  
 
CHAPTER 5: Operation and Diagnostics  
When the local and remote Multi-Function LD Cards are both powered up and  
are passing data normally, the LEDs on the Cards will look like this:  
• Power: Steadily lit  
• TD and RD: Flashing red and green  
• RTS and CD: Green steadily lit, red dark  
• Test and Error: Dark  
5.4 V.54 and V.52 Diagnostic Tests  
The Multi-Function LD Card offers two V.54 test modes and two V.52 test  
modes to evaluate the condition of the modems and the communication link.  
Both sets of tests can be activated physically from the front panel. The V.54  
test can also be activated from the RS-232 interface.  
NOTE  
V.54 and V.52 test modes on the Multi-Function LD Card are available for  
point-to-point applications only.  
5.4.1 LOCAL ANALOG LOOPBACK (LAL)  
The Local Analog Loopback (LAL) test checks the operation of the local  
Multi-Function LD Card, and is performed separately on each unit. Any data  
sent to the local Multi-Function LD Card in this test mode will be echoed  
(returned) back to the user device. For example, characters typed on the  
keyboard of a terminal will appear on the terminal’s screen. To perform a  
LAL test, follow these steps:  
1. Activate LAL. You can do this in either of two ways. One is to move the  
upper front-panel toggle switch labeled “Remote—Analog” to the  
“Analog” (right-hand) position. The other is to raise the signal on  
Pin 18 of the RS-232 interface (switch S3 position 5 must be “On”—see  
Section 3.1.4). Once LAL is activated, the Card’s transmit output is  
connected to its own receiver. The Test LED should light.  
2. Verify that the attached DTE is operating properly and can be used for a  
test.  
3. Move the lower front-panel toggle switch labeled “511/E—511” to the  
“511” (right-hand) position. This will activate the V.52 BERT test mode  
and inject a 511 test pattern into the local loop. If any errors are present  
in the loop, the Error LED will blink sporadically.  
33  
 
MULTI-FUNCTION LD CARD  
4. If the BERT test indicates no errors are present, move the “511/E—511”  
toggle switch to the left-hand position to activate the “511/E” test with  
periodic errors. If this test is working properly, the Error LED will blink  
regularly. A successful 511/E test will confirm that the loop is in place,  
and that the Multi-Function LD Card’s built-in 511 generator and  
detector are working properly.  
5. If the BERT test indicates that errors are present, make sure that the RS-  
232 cable connecting the DTE to the Multi-Function LD Card is wired  
straight-through, and is plugged in properly. Also, make sure that the  
Card is configured properly. Then recheck your DTE equipment. If you  
still get errors and can’t find the cause, call your supplier for technical  
support (see Section 6.1).  
5.4.2 REMOTE DIGITAL LOOPBACK (RDL)  
The Remote Digital Loopback (RDL) test checks the performance of both the  
local and remote Multi-Function LD Cards, and the communication link  
between them. Any characters sent to the remote Card in this test mode will  
be echoed (returned) back to the originating device. For example, characters  
typed on the keyboard of the local terminal will appear on the local terminal’s  
screen after having been passed to the remote Multi-Function LD Card and  
looped back. To perform an RDL test, follow these steps:  
1. Activate RDL. You can do this in either of two ways. One is to move the  
upper front-panel toggle switch labeled “Remote—Analog” to the  
“Remote” (left-hand) position. The other is to raise the signal on  
Pin 21 of the RS-232 interface (switch S3 position 6 must be “On”—see  
Section 3.1.4). Once RDL is activated, the remote Card’s receive input is  
connected to its own transmitter. The Test LED should light on both  
Cards.  
2. Verify that the DTE attached to the local Card is operating properly and  
can be used for a test.  
3. Move the lower front-panel toggle switch labeled “511/E—511” to the  
“511” (right-hand) position. This will activate the V.52 BERT test mode  
and inject a 511 test pattern into the remote loop. If any errors are  
present in the loop, the Error LED will blink sporadically.  
34  
 
CHAPTER 5: Operation and Diagnostics  
4. If the BERT test indicates no errors are present, move the “511/E—511”  
toggle switch to the left-hand position to activate the “511/E” test with  
periodic errors. If this test is working properly, the Error LED will blink  
regularly. A successful 511/E test will confirm that the loop is in place,  
and that the Multi-Function LD Card’s built-in 511 generator and  
detector are working properly.  
5. If the remote BERT test indicates that errors are present, but the local  
analog loopback BERT tests showed that both Multi-Function LD Cards  
were functioning properly, there is probably a problem with the twisted-  
pair communication line connecting the two modems. A common  
problem is improper crossing of the pairs. Also, check the cable’s  
pinning (see Section 4.5) and continuity. If you still get errors and can’t  
find the cause, call your supplier for technical support (see Section 6.1).  
5.4.3 USING THE V.52 BERT TEST INDEPENDENTLY  
The Multi-Function LD Card can perform its V.52 BERT test independently of  
the V.54 loopback tests. This requires two operators: one to initiate and  
monitor the test at the local Card, and one to do the same at the remote  
Card. To use the V.52 BERT test by itself, both operators should  
simultaneously follow these steps:  
1. Move the lower front-panel toggle switch labeled “511/E—511” to the  
“511” (right-hand) position. This will activate the V.52 BERT test mode  
and transmit a 511 test pattern to the other unit. If any errors are  
present, the receiving modem’s Error LED will blink sporadically.  
NOTE  
For this independent test to work properly, the “511/E—511” switch on  
both Multi-Function LD Cards must be set the same way (that is, moved  
to the “511” position for this step and to the “511/E” position for the next  
step).  
2. If the BERT test indicates no errors are present, move the “511/E—511”  
toggle switch to the left-hand position to activate the “511/E” test with  
periodic errors. If this test is working properly, the receiving modem’s  
Error LED will blink regularly. A successful 511/E test will confirm that  
the link is in place, and that the Multi-Function LD Cards’ built-in 511  
generators and detectors are working properly.  
35  
 
MULTI-FUNCTION LD CARD  
6. Troubleshooting  
6.1 Calling Your Supplier  
If you determine that your Multi-Function LD Card is malfunctioning, do not  
attempt to alter or repair it. Contact your supplier. The problem might be  
solvable over the phone.  
Before you do, make a record of the history of the problem. Your supplier  
will be able to provide more efficient and accurate assistance if you have a  
complete description, including:  
• The nature and duration of the problem.  
• When the problem occurs.  
• The components involved in the problem.  
• Any particular application that, when used, appears to create the problem  
or make it worse.  
6.2 Shipping and Packaging  
If you need to transport or ship your Multi-Function LD Card:  
• Package it carefully. We recommend that you use the original container.  
• Before you ship a unit for repair or return, contact your supplier to  
get a Return Authorization (RA) number, and make sure you include  
everything you received with the unit when you ship it.  
36  
 
APPENDIX: Cable Recommendations  
Appendix: Cable Recommendations  
The Multi-Function LD Card has been performance-tested using twisted-pair  
cable with these characteristics:  
Wire Gauge  
Capacitance  
Resistance  
19 AWG  
22 AWG  
24 AWG  
26 AWG  
83 nf/mi. or 15.72 pf/ft.*  
83 nf/mi. or 15.72 pf/ft.*  
83 nf/mi. or 15.72 pf/ft.*  
83 nf/mi. or 15.72 pf/ft.*  
16.3 /1000 ft. (53.5 /km)  
32.6 /1000 ft. (107 /km)  
51.65 /1000 ft. (169.5 /km)  
82.35 /1000 ft. (270.2 /km)  
*Alternatively, 51.6 nf/km or 51.6 pf/m  
If you use the Multi-Function LD Card with a different type of twisted-pair  
cable, make sure that the cable has characteristics similar to, or better than,  
those listed above (for example, lower capacitance or lower resistance).  
Bench tests yield the following data-rate/maximum-distance results:  
Data Rate  
in bps  
Maximum Distance in miles (km)  
19 AWG  
22 AWG  
24 AWG  
26 AWG  
57,600  
38,400  
28,800  
19,200  
14,400  
9600  
12 (19.3)  
13 (20.9)  
14 (22.5)  
16 (25.7)  
17 (27.4)  
18.5 (29.8)  
19 (30.6)  
19.5 (31.4)  
20 (32.2)  
20.5 (33)  
20.5 (33)  
20 (32.2)  
7 (11.3)  
7.5 (12.1)  
8 (12.9)  
5.3 (8.5)  
6.2 (10)  
4 (6.4)  
4.2 (6.8)  
4.6 (7.4)  
5.1 (8.2)  
6.5 (10.5)  
7.5 (12.1)  
8 (12.9)  
6.6 (10.6)  
7 (11.3)  
8.5 (13.7)  
11 (17.7)  
13 (20.9)  
13.5 (21.7)  
14 (22.5)  
14.5 (23.3)  
15 (24.1)  
15 (24.1)  
15 (24.1)  
9.2 (14.8)  
10.4 (16.7)  
10.9 (17.5)  
11.3 (18.2)  
11.5 (18.5)  
11.6 (18.7)  
11.5 (18.5)  
11.4 (18.3)  
7200  
4800  
8.8 (14.2)  
8.8 (14.2)  
9 (14.5)  
3600  
2400  
1800  
8.9 (14.3)  
8.9 (14.3)  
1200  
Many environmental factors can affect the maximum distances obtainable at a particular  
site. Use this table as a general guideline only.  
37  
 
MULTI-FUNCTION LD CARD  
To gain optimum performance from the Multi-Function LD Card, please  
keep these guidelines in mind:  
• Always use twisted-pair cable—this is not an option.  
• Use twisted-pair cable with a capacitance of 20 pf/ft. (65.6 pf/m) or less.  
• Avoid twisted-pair cable thinner than 26 AWG (that is, avoid higher AWG  
numbers than 26).  
• Using twisted-pair cable with a resistance greater than that listed at the  
top of this page might reduce the maximum distance you can run the  
cable, but should not otherwise affect your system.  
38  
 
© Copyright 1995. Black Box Corporation. All rights reserved.  
1000 Park Drive  
Lawrence, PA 15055-1018  
724-746-5500  
Fax 724-746-0746  
 

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