ppp.Devices - PPP physical device description file format
The file /etc/ppp/Devices associates dialer types with physical
devices and speeds. pppd examines it when placing a call to a
neighboring machine. If no suitable speed is found, or if all devices
associated with that speed are busy, pppd will try again later.
Entries are one to a line; blank lines are ignored. Comments begin
with a `#' and extend to the end of the line. Upper/lower case
distinctions are significant. Fields on a line are separated by
horizontal white space (blanks or tabs).
Each entry must contain three or more fields, in this order:
dialer Either the string `Direct', or the name of the modem
dialing chat script (found in Dialers) to use with this
device, or the name of an external dialer program.
device The name of the device in the /dev directory (ttya, cua,
etc.). Device names for SnapLink connections are followed
by a slash and the port number in use (rsd2a/0, rrz4a/2,
speed The baud rate of the synchronous connection, or a string
to be matched against the speed field of entries in
Systems when the Systems device field is set to ACU.
Speeds must either be valid async baud-rate numbers (as
found in <<<<sys/ttydev.h>>>>) or must begin with them (2400,
38400, 19200-PEP, etc.), or must be speeds of which the
SnapLink hardware is capable (9600, 56000, 64000, 1536000,
Any special handling for this device. Currently supported
xonxoff Specifies that the line be conditioned
for in-band (`software') flow control,
using the characters DC3 (^S, XOFF,
ASCII 0x13) to stop the flow and DC1
(^Q, XON, ASCII 0x11) to resume. The
default is to use no flow control. For
an outbound connection, this may be
specified either in Devices or on the
pppd command line.
internal-clocking The SnapLink will provide the
synchronous clock signal. By default,
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it expects the modem, CSU/DSU or modem
eliminator to provide the clock signal.
Internal-clocking cannot be used with
RS-232 cables on the SnapLink.
32-bit-fcs The SnapLink will calculate 32-bit FCS
values for transmitted frames, and check
received frames with 32-bit FCS
calculations. This is not negotiable at
connection establishment time. 32-bit
FCS is only available when running
synchronous PPP on the SnapLink.
The number of additional HDLC flag
characters the SnapLink should insert
between data frames. The default and
minimum is 2; the maximum is 16.
ignore-cd Ignore the state of the CD (Carrier
Detect, also called DCD, Data Carrier
Detect) signal. This is useful for
systems that don't support CD but want
to run PPP over a dedicated line.
The external dialer program is run with the following arguments:
device name The contents of the Device field from the Devices
speed The contents of the Speed field of the Systems and
telephone number The contents of the Phone Number field of the
optional parameters Copied from the Optional Parameters section of the
If the external dialer program exits with status 0, then the dial
attempt is considered to have succeeded. Any other exit status
indicates a failure.
# Devices - PPP devices file
#Dialer device speed Optional parameters
T2500-PEP cua 19200-PEP rtscts
T1600 cub 38400 rtscts
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Direct rsd0a/0 1536000 internal-clocking
Oddball rsd0a/1 64000 cua 9600 5551212
In the last line of this example, the 64Kb synchronous modem on the
SnapLink's port 1 has an asynchronous dialer interface attached to the
workstation's port `a'. The Systems line would look like
host Oddball rsd0a/1 64000 0
There must be a program (or an executable shell script) called
/etc/ppp/Oddball that dials the modem when invoked as
Oddball rsd0a/1 64000 0 cua 9600 5551212
A warning message will be printed for each unrecognized optional
parameter if the debug level is 2 or more.
The external dialer is invoked as root, so you should take appropriate
security precautions with its content and file protection.
ppp.Devices was developed by the Progressive Systems.
tun(4), ppp.Auth(4), ppp.Dialers(4), ppp.Filter(4), ppp.Keys(4),
ppp.Systems(4), pppd(1), RFC 1548, RFC 1332, RFC 1144, RFC 1055.
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