Raymar Telenetics MIU14.4L, User Manual

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0049-0867-01X 2
nd
Generation MIU14.4L – USER’S GUIDE 6/22/2011
Rev. A Page 27 of 39
14. DIAGNOSTICS
The following pages provide software and hardware techniques for diagnosing communication
problems and thereby isolating the problem at either the local modem, the remote modem or the
interconnecting line.
The following AT&Tn commands form part of the CCITT V.54 protocol and can be used for
diagnostic testing.
Note: &Tn commands can only be used when the modem is configured for &Q0 <CR>
(unbuffered/direct asynchronous mode).
&T0 TERMINATE TEST IN PROGRESS
If a V.54 loopback test is in progress as a result of executing an &Tn command, then the &T0
command will cause that test to be terminated, provided that the modem is in the command state or
a V.54 state that accepts commands from the DTE. See specific &Tn command descriptions for
termination actions.
&T1 INITIATE LOCAL ANALOG LOOPBACK (See Figure 2)
When the AT&T1 command is entered, the modem goes on hook and configures itself for analog
loopback. DSR is turned off (if &S1 is in effect), the analog loopback state is entered, and the test
timer is set to the value in S18. A connect result code is sent to the DTE, and the test timer then
begins its count down. The test terminates when the test timer expires. If S18 equals 0, then the
test must be terminated by an &T0, H0, or Z command. While any command may be entered
while the modem is in this test state, the modem response is not specified except for H0, &T0 and
Z, any of which will terminate the test. Upon termination of the test, the modem enters the
command state.
RESULT CODE DESCRIPTION
CONNECT When local analog loopback state is entered.
ERROR If any other &Tn test is active (except &T0) or if in the on-line command
state.
OK After test is stopped by test timer, the H0 command, or the &T0 command.