14-8
C
HAPTER
14: T
ESTING
THE
C
ONNECTION
Testing Using a
Built-in Test Pattern
(AT&T7)
This test option causes the modem to perform a remote digital loopback
test by sending a built-in test pattern. An internal error detector counts
any errors and, when the test is ended, sends the number of errors or 000
(no errors) to the screen.
Follow the steps below. However, you don't need to type anything during
this test. The modem sends only its final error count to your screen.
1
Send
AT&M0&N3S14.0=0
to prepare the Business Modem 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 the escape code (
+++
).
2
Establish a connection with the remote device.
3
If you haven't already done so, arrange with the remote user to
cooperate with the test.
If necessary, set the remote device to acknowledge the remote digital
loopback request. For example, older 3Com modems need to be set to
S16=8.
4
Send
AT&T7
to the modem. The modem enters remote digital loopback
mode, and the MR status light flashes.
The Business Modem sends its built-in test pattern to the remote device,
which loops it back to your Business Modem. You will not see the data on
your screen.
5
Send the escape code,
+++
, and then
AT&T0
to end the test. You can also
end the test by sending
ATH
,
ATZ
, or
ATZ!
Be careful, though, because
ATZ and ATZ! reset the Business Modem in addition to ending the test.
If you issue an invalid command, the Business Modem sends an ERROR
message. If you set Register S18, the Business Modem automatically ends
the test when the test timeout is reached. See the example in the
previous section,
Stopping a Test
for an example of using S18.
When the test ends, the Business Modem returns a three-digit code,
followed by OK. A code of 000 indicates no errors were found; a code of
255 indicates 255 or more errors.
Data errors indicate a problem with the remote device or with the phone
link.
6
Send
AT&M4
, unless you used a reset command (ATZ or ATZ!).
Summary of Contents for OfficeConnect 56K Business
Page 14: ...4 ABOUT THIS GUIDE ...
Page 32: ...1 18 CHAPTER 1 CONNECTING TO YOUR ISP ...
Page 42: ...3 6 CHAPTER 3 MODES OF OPERATION ...
Page 64: ...7 4 CHAPTER 7 CONTROLLING EIA 232 SIGNALING ...
Page 72: ...8 8 CHAPTER 8 CONTROLLING DATA RATES ...
Page 80: ...9 8 CHAPTER 9 ACCESSING AND CONFIGURING THE BUSINESS MODEM REMOTELY ...
Page 96: ...11 6 CHAPTER 11 FLOW CONTROL ...
Page 108: ...12 12 CHAPTER 12 HANDSHAKING ERROR CONTROL DATA COMPRESSION AND THROUGHPUT ...
Page 112: ...13 4 CHAPTER 13 DISPLAYING QUERYING AND HELP SCREENS ...
Page 124: ...14 12 CHAPTER 14 TESTING THE CONNECTION ...
Page 132: ...15 8 CHAPTER 15 TROUBLESHOOTING ...
Page 162: ...B 14 APPENDIX B ALPHABETIC COMMAND SUMMARY ...
Page 168: ...C 6 APPENDIX C FLOW CONTROL TEMPLATE ...
Page 210: ...14 GLOSSARY ...