Modem Initialization Strings - Watchguard Firebox X20E Reference Manual

nocrtscts
Disable hardware flow control (that is, RTS/CTS) on the serial port. If neither
the crtscts nor the nocrtscts option is given, the hardware flow control setting
for the serial port is left unchanged.
noipdefault
Disables the default behavior when no local IP address is specified, which is to
determine (if possible) the local IP address from the hostname. With this
option, the peer will have to supply the local IP address during IPCP
negotiation (unless it was specified explicitly on the command line or in an
options file).
nomagic
Disable magic number negotiation. With this option, pppd cannot detect a
looped-back line. This option should only be needed if the peer is buggy.
nopersist
Exit once a connection has been made and terminated. This is the default
unless the persist or demand option has been specified.
novjccomp
Disable the connection-ID compression option in Van Jacobson-style TCP/IP
header compression. With this option, pppd will not omit the connection-ID
byte from Van Jacobson compressed TCP/IP headers, nor ask the peer to do
so.
silent
Pppd will not transmit LCP packets to initiate a connection until a valid LCP
packet is received from the peer (as for the "passive" option with older
versions of pppd).
xonxoff
Use 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, and the portions marked with '_____'
specify what is to be sent to the modem:
Reference Guide
Modem initialization strings
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