INSYS Modem 336 LL
i-modul Modem 336 LL
Modem
Configuration
Aug-06
7
with
AT\N5
at MNP4.
Note
All settings must be saved using
AT&W
as they are otherwise lost when
the connection is restarted!
2.2
Transmit Level
It may be required to adjust the transmit level of the modem to adapt it to the path.
The transmit level is set at –15dBm by the manufacturer and can be changed in the S
registry (
ATS91
). Transmit levels from –15 dBm (
ATS91=15
) to -6 dBm (
ATS91=6
) may
be set. The transmit level should be set to the same setting on both sides.
Attention!
In practice, a lower transmit level is often better, also for longer paths,
than a level that is too high.
If a transmit level is too high, malfunctions due to maladjustments and reflections may
prevent the signals of the remote terminal at the receiving modem to be interpreted cor-
rectly.
Note
If connection problems occur, one should always try to first reduce the
transmit level.
Gradually, set the S91 registry to a lower value.
2.3
PING Mode as Connection Safeguard
The leased line modems have an additional connection safeguard built in, which pre-
vents a modem connection to “hang up”.
This connection safeguard sends a short test message to the remote terminal in cyclical
intervals (every 20 seconds). If a modem does not get a proper test message from the
remote terminal on the receive side within 120 seconds it assumes that the connection is
no longer established and tries to re-establish the connection.
The used test message is initiated by a pre-defined character in the S registry
(
ATS8=<n>
). Factory setting:
ATS8=3
According to the used protocol, it may be of advantage to change the initial character to
avoid unnecessary data transfer between the modems. All characters may be set with
the ASCII code 1..255.
ATS8=0
will completely deactivate the connection safeguard.
Note
The initial character must be set to the same character on both sides
to enable the modems to recognize the test messages of the remote
side. If different ping characters are set, the remote terminal will re-
ceive invalid characters and the connection will be interrupted in cycli-
cal intervals.
