Baer UniMod 01/I, Operation Manual

Page: 9 / 16

UniMod 01/I
9
Programming with the terminal software
First set your terminal program to the appropriate data rate and data format for reading out the
target device (i.e. meter). Use one of the AT commands (e.g. ATS0?, ATI, AT&V) to check whether
the modem answers. If you see the answer on the screen, the interface is working correctly.
Note:
Simply typing „AT“ does not result in an answer, because the modem is by default pro-
grammed not to send messages and echoes (Parameters ATQ1 and ATE0).
Important: The modem is factory programmed to "auto mode". This enables it to communicate
with maximum possible speed to the remote modem using data compression and error correcting.
The data rate between the modems is independent from the data rate between modem and target
device. This method has the advantage of superior immunity against line noise. If the UniMod is
called by an older modem. which doesn't support those features, it is possible, that no connection
can be established. In that case it is better, to use a fixed transmission speed (over phone line) and
disable the compression and error correcting feature (see commands ATFx, ATNx, AT\Nx,
AT+MS= ).
If multiple target devices are connected to the modem using different data rates, communication is
only possible in synchronous direct mode (see command AT\N1). In this operating mode the data
rates of the target devices are identical to the data rate over the phone line. This enables the call-
ing modem to determine the data rate, which is used to read the target device. The modem leaves
in direct mode all transmission parameters unchanged. Data compression and error correction are
disabled. But beware: In case of bad connection or noisy line it may be possible that the UniMod
doesn't hang up after the call has finished!
At the end of every programming the settings have to be saved permanently using the AT&W
command. This ensures that the parameters are restored after power failure.
Example:

Establish connection PC to modem (e.g. using the parametering adapter). Start terminal pro-
gram and set data rate correctly.
The modem does not reply to a simple "AT" command by default. In order to test communica-
tion you have to use a command which results always in an answer (e.g. "AT&V" displays the
actual configuration of). This should give an readable output on your screen.

Input "AT&F" to restore factory settings. Modem should reply "OK".

Select automatic answering: "ATS0=1", Modem reply: "OK".

Select error correction: "AT\N3", Modem reply: "OK".

DTR-control is ignored: "AT&D0", Modem reply: "OK".

Disable local flow control: "AT&K0", Modem reply: "OK".

Disable echo: Enter "ATE0", Modem reply: "OK".
With this setting the modem does not echo characters sent by the target device. Some meters
may not communicate correctly if they receive their own output.

Suppress modem result codes: Enter "ATQ1". No answer from modem.
This prevents the modem from sending result codes to the target device. The result codes can
cause trouble with some meters.

Save current parameters: Enter "AT&W". No answer if ATQ1 command issued before.

Parametering finished.