i-modul Modem 336 LL
Functions
6.8
Set Two-Wire or Four-Wire Operation
By pre-configured factory default, the i-modul Modem 336 LL 3.0 is either set for opera-
tion at a two-wire or a four-wire line. In some cases, it may be reasonable to change this
configuration, for example if the data transmission does not work correctly in one of the
operating modes. Which operating mode you use will depend on the conditions required
by your application. Basically, four-wire operation guarantees better transmission per-
formance compared to two-wire operation. The i-modul Modem 336 LL 3.0 can be ad-
justed to the amount of wires of the leased line where it will be operated.
Configuration with AT commands
To configure the i-modul Modem 336
LL 3.0 for two-wire operation, use the
command:
AT&L0
To configure the i-modul Modem 336
LL 3.0 for four-wire operation, use the
command:
AT&L1
Save the settings using
AT&W
6.9
Adjusting the Transmission Level
The transmission level of the i-modul Modem 336 LL 3.0 at the leased line can be ad-
justed. This may be necessary to ensure flawless data transmissions via the leased line.
For longer two-wire lines, a lower transmitting level than the preset one may be reason-
able, as reflections and echoes in the line may impede the communication between the
devices. For short four-wire lines, a transmitting level that is too high will cause distor-
tions. The unit of the dimension transmission level is -dBm.
By factory default, the transmission level is set to -15 dBm.
Configuration with AT commands
To set a transmission level, use the
command:
Enter values between 6 and 15 for the
level.
ATS91=<n>
To set the transmission level to -
10 dBm use the command:
ATS91=10
Save the settings using
AT&W
To establish the connection with the
new transmission level, reset the i-
modul Modem 336 LL 3.0:
ATZ
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