Remote Digital Loopback Test (At&T6); Remote Digital Loopback With Self-Test (At&T7) - ZyXEL Communications 2864 Series User Manual

Level field of the LCD screen will indicate LDL. The Elite model's TST LED indicator
will be ON.
This test can be initiated by the local modem when the modems are on-line.
Local Modem
Transmitter
A
Receiver
Remote Digital Loopback Test (AT&T6)
This test will request the remote modem to do a digital loopback. During testing,
the local modem will send a remote digital loopback request to the remote modem
according to V.54. If the remote modem supports V.54 and is programmed to grant
this kind of request, it will resend all of the received data back to the local modem,
and the local terminal or computer will receive all of the data it sends out. This test
is applicable when the remote modem and local modem both provide V.54 Remote
Digital Loopback capability. The Control Level field of the LCD screen of the initi-
ating modem will indicate RLB, and that of the accepting modem will indicate LDL.
The Elite 2864 modems will have the TST LED indicator ON during the test.
This test can be initiated by either modem when the modems are on-line.
Local Modem
DTE
A
Remote Digital Loopback with Self-test (AT&T7)
This test generates data from the modem itself instead of input data from the
RS-232 interface. The data will go through the same path as it would with the Re-
mote Digital Loopback Test. In asynchronous mode, the pattern consists of printa-
ble ASCII characters. You can see the results on the screen. In the synchronous
mode, the pattern is made up of scrambled binary 1 and the Throughput Meter of
the initiated modem will change to a Bit Error Rate Meter. The left reader displays
accumulated bit errors and the right reader displays accumulated bits sent. On the
Elite model, the TST LED flashes for any bit error. On the Omni 288 models, the
EC LED flashes for any bit error. This test is applicable when the remote and the lo-
B
LDL
Transmitter
B
Receiver
RLB
Remote Modem
Transmitter
~
~
B
~
~
Receiver
Remote Modem
~
~ ~
B
~
18–4
A
Transmitter
A
Receiver
LDL
DTE