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W&T
RS232 Serial Buffer
First „ATDS=0“ + CR is output. This command causes the con-
nected modem to dial the call number contained in its speed
call location 0 (see modem manual). Now the buffer expects
the identification command within 60s. If this does not arrive,
the buffer sends a „ATHO“ + CR, and after 10 minutes have
elapsed makes another dialing attempt.
Since modems from different manufacturers can vary widely in
their configuration options as well as in how they handle the
individual control lines, only some general prerequisites for mo-
dem operation of the TC Buffer can be described here. If you
are unsure or if there are difficulties, first consult the manual
for your modem.
Settings for modem operation on the buffer
Since the TC Buffer does not support all RS232 control lines,
only the RxD, TxD and ground lines should be connected on
the modem. Handshaking should be set for Xon/Xoff.
Settings on the modem
The internal speed dial memory of the modem must contain the
call number to be dialed when there is a memory overflow
(AT&ZO=[call number]). The evaluation and handling of the
RTS and DTR control inputs and of the CTS and DSR outputs
should be turned off (AT&DO, AT&R1, AT&SO). If possible, flow
control should be configured for transparent Xon/Xoff.
Summary of Contents for RS232 88102
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