Testing the Business Modem using AT&Tn
14-5
Digital Loopback
Testing (AT&T3)
This test can help you locate a problem with a remote device or with the
telephone line. The figure below shows the data flow during Digital
Loopback (DL) testing.
1
Send the command
AT&M0&N3S14.0=0
to the modem to prepare for
testing.
This command disables error control, fixes the connection rate at 2400
bps, and makes the Business Modem return to command mode when
you type +++.
2
Establish a connection with the remote device.
3
Send the Business Modem the escape code,
+++
, to bring it back to
Command mode.
4
Send
AT&T3
to the modem to enter Digital Loopback mode.
5
Have the remote user type a short message. It will be looped back by your
Business Modem's transmitter for verification on the remote user's
screen. You will not see the message or any other data.
6
When the remote user has completed the test, send the escape code,
+++
, and then
AT&T0
to end the test.
Alternatively, you can end the test by sending ATH or ATZ. Be careful,
because ATZ resets the modem in addition to ending the test.
In any case, the Business Modem responds OK. If the modem sends an
ERROR message, you have issued an invalid command.
7
Send
AT&M4
, unless you used ATZ.
Содержание U.S. Robotics 56K Voice
Страница 1: ...http www 3com com 3Com OfficeConnect 56K Business Modem Command Reference Published January 1999...
Страница 14: ...4 ABOUT THIS GUIDE...
Страница 32: ...1 18 CHAPTER 1 CONNECTING TO YOUR ISP...
Страница 42: ...3 6 CHAPTER 3 MODES OF OPERATION...
Страница 64: ...7 4 CHAPTER 7 CONTROLLING EIA 232 SIGNALING...
Страница 72: ...8 8 CHAPTER 8 CONTROLLING DATA RATES...
Страница 80: ...9 8 CHAPTER 9 ACCESSING AND CONFIGURING THE BUSINESS MODEM REMOTELY...
Страница 96: ...11 6 CHAPTER 11 FLOW CONTROL...
Страница 108: ...12 12 CHAPTER 12 HANDSHAKING ERROR CONTROL DATA COMPRESSION AND THROUGHPUT...
Страница 112: ...13 4 CHAPTER 13 DISPLAYING QUERYING AND HELP SCREENS...
Страница 124: ...14 12 CHAPTER 14 TESTING THE CONNECTION...
Страница 132: ...15 8 CHAPTER 15 TROUBLESHOOTING...
Страница 162: ...B 14 APPENDIX B ALPHABETIC COMMAND SUMMARY...
Страница 168: ...C 6 APPENDIX C FLOW CONTROL TEMPLATE...
Страница 210: ...14 GLOSSARY...