Intelimax+4G User Manual
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Modem Emulation TAB
Function Description
Modem emulation assists in the transition from Circuit Switched Data (CSD) to Packet
Switched Data(PSD)/IP. If the control centre management system supports IP but the
field devices only support dialling back to the control centre using CSD, then you can
use the Intelimax+ to emulate the CSD modem interface. The Intelimax+ can also be
configured to act as an IP stack server for incoming connections if necessary.
Dialling Process
From the perspective of the field device it will dial out a CSD data call like it always does,
except the Intelimax+ will instead establish an IP stack client connection to the server. For
example, the field equipment may dial the following string: ‘ATDT0412123456’, then wait
for the connection to be established by receiving a ‘CONNECT’ message. The Intelimax+
can be configured to establish an IP stack client connection to one of the several
different server IP addresses depending on the number dialled.
Important: for the dial command, only ONE control character, which is CR or LF, can be
put immediately after the number to be dialled, e.g. ATDT0412123456<CR>.
Configuration
Modem Emulation will always generate a TCP Client connection to a remote server
based on the number and the associated TCP destination. The Intelimax+ must be
configured in IP Stack Auto or Manual mode with IP Stack in Server mode. This
configuration can be made using the Intelimax+ GUI or via AT commands. If the
Intelimax+ is in IP Stack Manual mode, then it will only connect to the network when it
receives the ATDT command via serial and will drop the connection when the call is
hung up (+++, ATH).
If the Intelimax+ is in IP stack Auto mode, then the modem will act as an IP stack server
and therefore could be addressed remotely. If a remote TCP client is making connection
to the modem, the modem will act as if an incoming CSD call is made and a connection
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