CXR V.34bis series, Operation And Installation Manual, Page: 82 / 150

Leased Line Operation
78
V.34bis Series Standalone & Rackmount Modems
ookback
and S56 is set greater than zero, the
following will happen: The modem, detecting that the leased line is
will attempt ne. If the training fails, the
ll go back t
. From the
S56 before attempting a lookback.
Set one modem to be
LEASED LINE ANSW
memory.
b
connection in 30 seco initiated
e
ils, the modems w
ill dial the
phone number with the "A" attribute, and the answering modem should
answer the ring and connect. The speaker will emit a tone every second to
announce the leased line is down, but it can be turned off by pressing
DL/DIS button momentarily or by the AT%V0 command.
If leased line lookback is enabled, the originate modem will transmit a 0
dBm pilot tone every two seconds to the leased line and wait for response
from the answering modem.
The answering modem, when detecting the pilot tone, will send back a 1/2
second tone, hold the dial line, go back to the leased line and start training.
The originate modem, when detecting a tone from remote modem, will hold
the dial line, go back to the leased line and start training for 15 seconds.
If the training is not successful, both modems will switch back to the dial line
and re-establish the connection.
L
When leased line lookback option is enabled the lookback timer S-Register
56 should be enabled.
ATS56=n Wait for n (0-255) minutes interval, then lookback at the
leased line for 10 seconds; n=0 is constant lookback.
When auto-lookback is enabled
restored, to retrain on the leased li
modem wi
takes over
o the dial-up line. This will happen once before S56
n on, the modem will wait for the time period stored in
in LEASED LINE ORIGINATE and the other to be in
ER (AT%On command). Save options to non-volatile
Press "DL/DIS" on oth modems. The modems should establish the
nds. Each time a leased line connection is
the stored leased lin
configuration
defaults will be reloaded. This allows the dial back up
settings to be different from the leased line. If the leased line
ill try to retrain. fa
If dial back up is not enabled, the modem will wait for the leased line to be
back in operation, then start training and establish the connection.
If dial back up is enabled, the modems will try to train on the leased line for
15 seconds. If not successful, the originate mode modem w