Multitech MT5634ZBA-USB Betriebsanweisung PDF herunterladen (Seite 55)

Appendix C - Loopback Tests

Remote Digital Loopback Test (V.54 Loop 2)

The remote digital loopback test tests the phone lines and the circuits of both your

modem and a remote modem. In this test, your modem must be on line with another

modem that is set up to respond to a request for remote digital loopback. (Note that

some modems might not support remote digital loopback or might have it disabled.) Data

from your computer or terminal is transmitted through your modem and over the phone

line to the remote modem, where it is then looped back to your modem.

AT&T6

Computer or Terminal Local MultiModem Remote MultiModem Computer or Terminal

Digital Analog DigitalAnalog

AT&T6

UUUUUUUUU

UUUUU

Figure C-2. Remote digital loopback test.

Test Procedure

1. Arrange to have &T6 set on the remote test modem.

2. Open your communications software and go into terminal mode. Type AT and press

ENTER; you should get an OK message. Type AT\N and press ENTER to disable

error correction.

3. Dial the remote modem and establish your online connection.

4. Type the escape sequence +++AT and press ENTER to bring your modem into

online command mode.

5. Type AT&T6 and press ENTER. The local modem responds to this command by

transmitting an unscrambled marking signal, which causes the remote modem to

place itself in digital loopback mode. Then the local modem exits online command

mode and enters data mode.

6. Enter data from your keyboard. For this test, typing multiple uppercase U characters

is a good way to send an alternating test pattern of binary ones and zeroes. Data

received by the remote modem enters its analog receiver, is converted to digital data,

is reconverted into analog, and then is transmitted back to your modem. Your modem

passes this test if the data received on your monitor is the same as the data entered

from your keyboard.

7. To exit the test, type the escape sequence +++AT and press ENTER. This puts the

modem in online command mode. The modem should respond with an OK message.

If you wish to stay on line with the remote modem for normal data transmission, type

AT&T and press ENTER to exit the test, then type ATO and press ENTER to return

on line. If you wish to terminate the call, type ATH and press ENTER to hang up.

1 2 ... 50 51 52 53 54 55 56 57 58 59 60 61 62

Keine Kommentare

Multitech MT5634ZBA-USB Betriebsanweisung Seite 55