158
Appendix I - Testing Your MMH 2834
I.8 Digital Loopback Test (Rem/Auto)(Sync
Mode)
This test must be run when you have a data connection with another
modem. In this test, data is passed to the remote modem and is looped
back to the local modem (as if an ATU2 command was issued in
Asynchronous test mode), as shown in Figure I-6. This lets you test the
local and remote modem’s transmit and receive circuits, as well as your
computer’s serial COM port and the phone lines. If the test results in a
mismatch of entered/received data (multiple upper case “U” characters
in Figure I-6), the Local Analog Loopback Test should be performed on
both the remote and local modems. If that test is successful, the problem
format is sync. Sync mode is set usng the $M(Sync) command. Once
you receive an OK message from your modem (if responses are
enabled), the local modem is placed in Digital Loopback mode.
UUUUU
UUUUU
&T4 Command
DIP-Switch #9
DOWN;
Answ/Orig
Switch Toggled
to Answ
position when
On-line
Computer or Terminal
Local MultiModem
Remote MultiModem
Computer or Terminal
Digital
Analog
Digital
Analog
Figure I-6. Digital Loopback Test (remote/automatic) (Synchronous
Mode)
Summary of Contents for MMH900
Page 1: ...MMH900 Series Statistical Multiplexer User Guide...
Page 7: ...Chapter 1 Introduction Description...
Page 26: ...Chapter 2 Configuration...
Page 33: ...Chapter 3 Front Rear Panel Descriptions...
Page 44: ...Chapter 4 Installation...
Page 51: ...Chapter 5 Commands...
Page 89: ...Chapter 6 Operating Procedures...
Page 96: ...Chapter 7 Troubleshooting...
Page 111: ...Chapter 8 Service Warranty Technical Support...
Page 116: ...Appendices...
Page 184: ...Glossary...
Page 193: ...Glossary 193 X Y Z...
Page 200: ...S000315A...