3Com 56K manual Testing Using Keyboard Data ATS16=8

14-10CHAPTER 14: TESTING THE CONNECTION

Testing Using

Keyboard Data

(ATS16=8)

1Send 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 (+++).

2Establish a connection with the remote device.

3If 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. 3Com modems should be set to &T4. (Older 3Com modems should be set to S16=8.)

4Send the Business Modem ATS16=8O.

The Business Modem enters remote digital loopback mode and then goes back online (O command). It then transmits the test signals, causing the remote device to enter remote digital loopback mode. The MR status light flashes during this operation.

5Type a short message. It will be looped back to your Business Modem by the remote device and to your screen for verification. (The remote user will not see your data.)

6Send the escape code, +++, and then ATS16=0 to end 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.

If you wish to resume data transmission with the remote device, add the O command (ATO) after the ATS16=0 string to return online. If you do this, remember that error control is disabled. Because error control is negotiated during the connection sequence, its status cannot be changed until the Business Modem is back on hook and in Command mode.

7Send AT&M4, unless you used a reset command (ATZ or ATZ!).