similarity index 58%
rename from Documentation/networking/baycom.txt
rename to Documentation/networking/baycom.rst
@@ -1,26 +1,31 @@
- LINUX DRIVERS FOR BAYCOM MODEMS
+.. SPDX-License-Identifier: GPL-2.0
- Thomas M. Sailer, HB9JNX/AE4WA, <sailer@ife.ee.ethz.ch>
+===============================
+Linux Drivers for Baycom Modems
+===============================
-!!NEW!! (04/98) The drivers for the baycom modems have been split into
+Thomas M. Sailer, HB9JNX/AE4WA, <sailer@ife.ee.ethz.ch>
+
+The drivers for the baycom modems have been split into
separate drivers as they did not share any code, and the driver
and device names have changed.
This document describes the Linux Kernel Drivers for simple Baycom style
-amateur radio modems.
+amateur radio modems.
The following drivers are available:
+====================================
baycom_ser_fdx:
This driver supports the SER12 modems either full or half duplex.
- Its baud rate may be changed via the `baud' module parameter,
+ Its baud rate may be changed via the ``baud`` module parameter,
therefore it supports just about every bit bang modem on a
serial port. Its devices are called bcsf0 through bcsf3.
This is the recommended driver for SER12 type modems,
however if you have a broken UART clone that does not have working
- delta status bits, you may try baycom_ser_hdx.
+ delta status bits, you may try baycom_ser_hdx.
-baycom_ser_hdx:
+baycom_ser_hdx:
This is an alternative driver for SER12 type modems.
It only supports half duplex, and only 1200 baud. Its devices
are called bcsh0 through bcsh3. Use this driver only if baycom_ser_fdx
@@ -37,45 +42,48 @@ baycom_epp:
The following modems are supported:
-ser12: This is a very simple 1200 baud AFSK modem. The modem consists only
- of a modulator/demodulator chip, usually a TI TCM3105. The computer
- is responsible for regenerating the receiver bit clock, as well as
- for handling the HDLC protocol. The modem connects to a serial port,
- hence the name. Since the serial port is not used as an async serial
- port, the kernel driver for serial ports cannot be used, and this
- driver only supports standard serial hardware (8250, 16450, 16550)
+======= ========================================================================
+ser12 This is a very simple 1200 baud AFSK modem. The modem consists only
+ of a modulator/demodulator chip, usually a TI TCM3105. The computer
+ is responsible for regenerating the receiver bit clock, as well as
+ for handling the HDLC protocol. The modem connects to a serial port,
+ hence the name. Since the serial port is not used as an async serial
+ port, the kernel driver for serial ports cannot be used, and this
+ driver only supports standard serial hardware (8250, 16450, 16550)
-par96: This is a modem for 9600 baud FSK compatible to the G3RUH standard.
- The modem does all the filtering and regenerates the receiver clock.
- Data is transferred from and to the PC via a shift register.
- The shift register is filled with 16 bits and an interrupt is signalled.
- The PC then empties the shift register in a burst. This modem connects
- to the parallel port, hence the name. The modem leaves the
- implementation of the HDLC protocol and the scrambler polynomial to
- the PC.
+par96 This is a modem for 9600 baud FSK compatible to the G3RUH standard.
+ The modem does all the filtering and regenerates the receiver clock.
+ Data is transferred from and to the PC via a shift register.
+ The shift register is filled with 16 bits and an interrupt is signalled.
+ The PC then empties the shift register in a burst. This modem connects
+ to the parallel port, hence the name. The modem leaves the
+ implementation of the HDLC protocol and the scrambler polynomial to
+ the PC.
-picpar: This is a redesign of the par96 modem by Henning Rech, DF9IC. The modem
- is protocol compatible to par96, but uses only three low power ICs
- and can therefore be fed from the parallel port and does not require
- an additional power supply. Furthermore, it incorporates a carrier
- detect circuitry.
+picpar This is a redesign of the par96 modem by Henning Rech, DF9IC. The modem
+ is protocol compatible to par96, but uses only three low power ICs
+ and can therefore be fed from the parallel port and does not require
+ an additional power supply. Furthermore, it incorporates a carrier
+ detect circuitry.
-EPP: This is a high-speed modem adaptor that connects to an enhanced parallel port.
- Its target audience is users working over a high speed hub (76.8kbit/s).
-
-eppfpga: This is a redesign of the EPP adaptor.
+EPP This is a high-speed modem adaptor that connects to an enhanced parallel
+ port.
+ Its target audience is users working over a high speed hub (76.8kbit/s).
+eppfpga This is a redesign of the EPP adaptor.
+======= ========================================================================
All of the above modems only support half duplex communications. However,
the driver supports the KISS (see below) fullduplex command. It then simply
starts to send as soon as there's a packet to transmit and does not care
about DCD, i.e. it starts to send even if there's someone else on the channel.
-This command is required by some implementations of the DAMA channel
+This command is required by some implementations of the DAMA channel
access protocol.
The Interface of the drivers
+============================
Unlike previous drivers, these drivers are no longer character devices,
but they are now true kernel network interfaces. Installation is therefore
@@ -88,20 +96,22 @@ me for WAMPES which allows attaching a kernel network interface directly.
Configuring the driver
+======================
Every time a driver is inserted into the kernel, it has to know which
modems it should access at which ports. This can be done with the setbaycom
utility. If you are only using one modem, you can also configure the
driver from the insmod command line (or by means of an option line in
-/etc/modprobe.d/*.conf).
+``/etc/modprobe.d/*.conf``).
+
+Examples::
-Examples:
modprobe baycom_ser_fdx mode="ser12*" iobase=0x3f8 irq=4
sethdlc -i bcsf0 -p mode "ser12*" io 0x3f8 irq 4
Both lines configure the first port to drive a ser12 modem at the first
-serial port (COM1 under DOS). The * in the mode parameter instructs the driver to use
-the software DCD algorithm (see below).
+serial port (COM1 under DOS). The * in the mode parameter instructs the driver
+to use the software DCD algorithm (see below)::
insmod baycom_par mode="picpar" iobase=0x378
sethdlc -i bcp0 -p mode "picpar" io 0x378
@@ -115,29 +125,33 @@ Note that both utilities interpret the values slightly differently.
Hardware DCD versus Software DCD
+================================
To avoid collisions on the air, the driver must know when the channel is
busy. This is the task of the DCD circuitry/software. The driver may either
utilise a software DCD algorithm (options=1) or use a DCD signal from
the hardware (options=0).
-ser12: if software DCD is utilised, the radio's squelch should always be
- open. It is highly recommended to use the software DCD algorithm,
- as it is much faster than most hardware squelch circuitry. The
- disadvantage is a slightly higher load on the system.
+======= =================================================================
+ser12 if software DCD is utilised, the radio's squelch should always be
+ open. It is highly recommended to use the software DCD algorithm,
+ as it is much faster than most hardware squelch circuitry. The
+ disadvantage is a slightly higher load on the system.
-par96: the software DCD algorithm for this type of modem is rather poor.
- The modem simply does not provide enough information to implement
- a reasonable DCD algorithm in software. Therefore, if your radio
- feeds the DCD input of the PAR96 modem, the use of the hardware
- DCD circuitry is recommended.
+par96 the software DCD algorithm for this type of modem is rather poor.
+ The modem simply does not provide enough information to implement
+ a reasonable DCD algorithm in software. Therefore, if your radio
+ feeds the DCD input of the PAR96 modem, the use of the hardware
+ DCD circuitry is recommended.
-picpar: the picpar modem features a builtin DCD hardware, which is highly
- recommended.
+picpar the picpar modem features a builtin DCD hardware, which is highly
+ recommended.
+======= =================================================================
Compatibility with the rest of the Linux kernel
+===============================================
The serial driver and the baycom serial drivers compete
for the same hardware resources. Of course only one driver can access a given
@@ -154,5 +168,7 @@ The parallel port drivers (baycom_par, baycom_epp) now use the parport subsystem
to arbitrate the ports between different client drivers.
vy 73s de
+
Tom Sailer, sailer@ife.ee.ethz.ch
+
hb9jnx @ hb9w.ampr.org
@@ -41,6 +41,7 @@ Contents:
arcnet
atm
ax25
+ baycom
.. only:: subproject and html
- add SPDX header; - adjust titles and chapters, adding proper markups; - mark code blocks and literals as such; - mark tables as such; - adjust identation, whitespaces and blank lines; - add to networking/index.rst. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> --- .../networking/{baycom.txt => baycom.rst} | 110 ++++++++++-------- Documentation/networking/index.rst | 1 + 2 files changed, 64 insertions(+), 47 deletions(-) rename Documentation/networking/{baycom.txt => baycom.rst} (58%)