3Com 56K manual AT&T6, AT&T7, Phone line. Data flow is shown in the figure below, Request AT&T4

14-6	(AT&T6, AT&T7)	￿￿	￿￿￿￿￿	￿￿￿￿￿￿￿￿￿￿￿	￿￿￿￿￿	￿￿￿￿￿	￿￿￿￿￿￿￿￿￿￿￿	￿￿￿￿￿	￿￿
	CHAPTER 14: TESTING THE CONNECTION
	Remote Digital	The remote digital loopback test, verifies the condition of both devices
	Loopback Testing	and of the phone line. Data flow is shown in the figure below.

Data Flow During Remote Digital Loopback.

The request for and granting of remote digital loopback testing requires that both devices use ITU-T V.22 standard signaling. If the remote device does not have the capability or is not set to respond (with AT&T4), you will get an ERROR result code.

There are two remote digital loopback options.

If you want to	Command
Send keyboard data to the modem and verify it when it is	AT&T6
returned over the phone lines and to your screen
Have the modem send its internal test pattern and return	AT&T7
an error count to your screen

Example: Sending AT&T6 will verify keyboard data sent to the modem by returning it over the phone lines and displaying it on your screen.

Granting a Digital Using AT&T4 causes the Business Modem to grant a remote device's Loopback Test request for a remote digital loop-back test.

Request (AT&T4)

Canceling All Digital Using AT&T5 cancels AT&T4, and the Business Modem fails to Loopback Test acknowledge remote digital loopback test requests. This is the default so Requests (&T5) that your Business Modem isn't subject to another user calling and tying

up your Business Modem without your permission.