Testing the Business Modem using S-Resister 16
14-9
Testing the Business
Modem using
S-Resister 16
Register S16 is a bit-mapped register (See Appendix A,
S-Registers
, for
instructions for setting bit-mapped registers).
Earlier modems require bit 3 to be enabled to grant digital loopback
testing to a remote device. The Business Modem requires the &T4 setting
instead. To perform remote digital loopback testing with a modem that
does not use the &T test command, that modem should be set to S16=8.
Analog Loopback (AL)
S16=1D
To use the modem's Test Pattern (S16, bit 2) instead of typing your own
data, see RDL Testing Using a Built-in Test Pattern (S16=4).
1
Send
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
Send
ATS16=1D
. The modem enters AL mode and sends a CONNECT
result code. The MR status light flashes.
3
Type data to the modem for it to transmit, loop to its receiver, and output
to the screen.
An alternative is to use the Test Pattern, described later.
4
Send the escape code,
+++
, and then
ATH
to end the test.
5
Send
AT&M4
, unless you used a reset command (ATZ or ATZ!).
For your modem to use Use one of these command
Remote digital loopback with built-in test pattern
ATS16=4
or
ATS16.2=1
Remote digital loopback using keyboard data
ATS16=8
or
ATS16.3=1
