User guide

Modem Initialization Strings
Reference Guide 113
xonxoff
Uses software flow control (that is, XON/XOFF) to control the
flow of data on the serial port.
Modem Initialization Strings
These parameters specify a chat session that occurs between the Firebox
and the modem to properly initialize the modem. In most cases the
default initializations work with a wide variety of modems. The default
initializations are known to work with the list of approved modems.
In the default initializations below, the parameters marked with ^ specify
what the Firebox should expect back from the modem, while the portions
marked with _____ specify what the Firebox sends to the modem:
Explanation of fields
1 Specifies that the Firebox should expect nothing back from the
modem at this point in the chat.
2 Specifies that three plus characters (+++) should be sent with short
pauses in between, then a 1-second delay, then a return character, a
short pause, then the characters “ATH” are sent, finally followed by a
carriage return (which is not shown, but implied). This sequence
commands most modems to hang up.
3 Specifies that the Firebox should expect nothing back from the
modem at this point in the chat.
4 Send a 1-second delay followed by the characters “AT&F” to
command the modem to recall its factory-default configuration.
5 Expect “OK” back from the modem.
6 Send “ATE0” to the modem, which directs it not to echo back
command characters sent.
"" +\p+\p+\d\r\pATH "" \dAT&F OK ATE0 OK ATS0=1 OK
^^ ________________ ^^ ______ ^^ ____ ^^ ______ ^^
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