Section Four

&Tn — T est and Diagnostic

Parameters

0, 1, or 3 through 8

Default4

Selects the test command. Test commands must be initiated in the command mode with asynchronous operation in the Direct mode selected (&Q0) at a speed of less than 14400 or 28800 (28800 version only).

A telco line connection must be established prior to initiating digital loopback tests. If these conditions are not met, the modem issues the ERROR result code. If local analog loopback is initiated while the modem is connected, the modem disconnects before performing the test.

An initiated test is active for a period of time specified by register S18 (test timer) before returning to the command mode. If S18 is zero, the test aborts when the user issues the &T0 command.

Examples

AT&T0

End test in progress. The escape sequence (+++)

 

must be issued to return the modem to the

 

command mode prior to sending this command.

 

Subsequent issuing of the O command while in the

 

command mode will cause the local and remote

 

modems to return to normal data mode operation if

 

the interrupted test was digital loopback.

AT&T1

Initiates local analog loopback. This test verifies the

 

working condition of the path between the local

 

communications software and the local modem. The

 

characters received from the communications

 

software are looped back by the modem.

AT&T3

Initiates remote digital loopback locally. The

 

characters received from the remote modem are

 

looped back to the remote modem by the local

 

modem. This test verifies the working condition of

 

the path from a remote modem, through a local

 

modem, and back to the remote modem.

AT&T4

Allows the modem to respond to a request from a

 

remote modem for a remote digital loopback test.

AT&T5

Prohibits the modem from granting a request from a

 

remote modem for a digital loopback test.

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Trumpcard 14400/28800 Modem

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Ositech comm Trumpcard Data/Fax Modem manual Tn T est and Diagnostic