SYNCINIT(8) Maintenance Commands and Procedures SYNCINIT(8)

NAME

syncinit - set serial line interface operating parameters

SYNOPSIS

/usr/sbin/syncinit device
[ [baud_rate] | [keyword=value,]... | [single-word option]]

DESCRIPTION

The syncinit utility allows the user to modify some of the hardware
operating modes common to synchronous serial lines. This can be
useful in troubleshooting a link, or necessary to the operation of a
communications package.


If run without options, syncinit reports the options as presently set
on the port. If options are specified, the new settings are reported
after they have been made.

OPTIONS

Options to syncinit normally take the form of a keyword, followed by
an equal sign and a value. The exception is that a baud rate may be
specified as a decimal integer by itself. Keywords must begin with
the value shown in the options table, but may contain additional
letters up to the equal sign. For example, loop= and loopback= are
equivalent.


The following options are supported:


Keyword Value Effect
loop yes Set the port to operate
in internal loopback
mode. The receiver is
electrically
disconnected from the
DCE receive data input
and tied to the
outgoing transmit data
line. Transmit data is
available to the DCE.
The Digital
Phase-Locked Loop
(DPLL) may not be used
as a clock source in
this mode. If no other
clocking options have
been specified, perform
the equivalent of
txc=baud and rxc=baud.
no Disable internal
loopback mode. If no
other clocking options
have been specified,
perform the equivalent
of txc=txc and rxc=rxc.
echo yes Set the port to operate
in auto-echo mode. The
transmit data output is
electrically
disconnected from the
transmitter and tied to
the receive data input.
Incoming receive data
is still visible. Use
of this mode in
combination with local
loopback mode has no
value, and should be
rejected by the device
driver. The auto-echo
mode is useful to make
a system become the
endpoint of a remote
loopback test.
no Disable auto-echo mode.
nrzi yes Set the port to operate
with NRZI data
encoding.
no Set the port to operate
with NRZ data encoding.
txc txc Transmit clock source
will be the TxC signal
(pin 15).
rxc Transmit clock source
will be the RxC signal
(pin 17).
baud Transmit clock source
will be the internal
baud rate generator.
pll Transmit clock source
will be the output of
the DPLL circuit.
rxc rxc Receive clock source
will be the RxC signal
(pin 17).
txc Receive clock source
will be the TxC signal
(pin 15).
baud Receive clock source
will be the internal
baud rate generator.
pll Receive clock source
will be the output of
the DPLL circuit.
speed integer Set the baud rate to
integer bits per
second.


There are also several single-word options that set one or more
parameters at a time:


Keyword Equivalent to Options:
external txc=txc rxc=rxc loop=no
sender txc=baud rxc=rxc loop=no
internal txc=pll rxc=pll loop=no
stop speed=0

EXAMPLES

Example 1: Using syncinit

The following command sets the first CPU port to loop internally,
using internal clocking and operating at 38400 baud:


example# syncinit zsh0 38400 loop=yes
device: /dev/zsh ppa: 0
speed=38400, loopback=yes, echo=no, nrzi=no, txc=baud, rxc=baud


The following command sets the same port's clocking, local loopback
and baud rate settings to their default values:


example# syncinit zsh0 stop loop=no
device: /dev/zsh ppa: 0
speed=0, loopback=no, echo=no, nrzi=no, txc=txc, rxc=rxc

SEE ALSO

Intro(2), ioctl(2), attributes(7), syncloop(8), syncstat(8)

DIAGNOSTICS

device missing minor device number

The name device does not end in a decimal number that can be
used as a minor device number.


bad speed: arg

The string arg that accompanied the speed= option could not be
interpreted as a decimal integer.


Bad arg: arg

The string arg did not make sense as an option.


ioctl failure code = errno

An ioctl(2) system called failed. The meaning of the value of
errno may be found in Intro(2).

WARNINGS

Do not use syncinit on an active serial link, unless needed to
resolve an error condition. Do not use this command casually or
without being aware of the consequences.

March 6, 2023 SYNCINIT(8)