patch-2.1.49 linux/drivers/net/README.baycom

• Lines: 119
• Date: Tue Aug 5 09:49:50 1997
• Orig file: v2.1.48/linux/drivers/net/README.baycom
• Orig date: Wed Oct 30 04:15:12 1996

diff -u --recursive --new-file v2.1.48/linux/drivers/net/README.baycom linux/drivers/net/README.baycom
@@ -1,118 +0,0 @@
-		    LINUX DRIVER FOR BAYCOM MODEMS
-
-       Thomas M. Sailer, HB9JNX/AE4WA, <sailer@ife.ee.ethz.ch>
-
-This document describes the Linux Kernel Driver for simple Baycom style
-amateur radio modems. The driver supports the following modems:
-
-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.
-
-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.
-
-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 
-access protocol.
-
-
-The Interface of the driver
-
-Unlike previous drivers, the driver is no longer a character device,
-but it is now a true kernel network interface. Installation is therefore
-simple. Once installed, four interfaces named bc[0-3] are available.
-sethdlc from the ax25 utilities may be used to set driver states etc.
-Users of userland AX.25 stacks may use the net2kiss utility (also available
-in the ax25 utilities package) to converts packets of a network interface
-to a KISS stream on a pseudo tty. There's also a patch available from
-me for WAMPES which allows attaching a kernel network interface directly.
-
-
-Configuring the driver
-
-Every time the 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/conf.modules).
-
-Examples:
-  insmod baycom modem=1 iobase=0x3f8 irq=4 options=1
-  sethdlc -i bc0 -p type ser12 io 0x3f8 irq 4 options 1
-
-Both lines configure the first port to drive a ser12 modem at the first
-serial port (COM1 under DOS). options=1 instructs the driver to use
-the software DCD algorithm (see below).
-
-  insmod baycom modem=2 iobase=0x378 irq=7 options=1
-  sethdlc -i bc0 -p type par96 io 0x378 irq 7 options 1
-
-Both lines configure the first port to drive a par96 or par97 modem at the
-first parallel port (LPT1 under DOS). options=1 instructs the driver to use
-the software DCD algorithm (see below).
-  
-The channel access parameters can be set with sethdlc -a or kissparms.
-Note that both utilities interpret the values slightly different.
-
-
-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.
-
-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.
-
-
-
-Compatibility with the rest of the Linux kernel
-
-The serial driver, the line printer (lp) driver and the baycom driver compete
-for the same hardware resources. Of course only one driver can access a given
-interface at a time. The serial driver grabs all interfaces it can find at
-startup time. Therefore the baycom driver subsequently won't be able to
-access a serial port. You might therefore find it necessary to release
-a port owned by the serial driver with 'setserial /dev/ttyS# uart none', where
-# is the number of the interface. The baycom driver does not reserve any
-port at startup, unless one is specified on the 'insmod' command line. Another
-method to solve the problem is to compile all three drivers as modules and
-leave it to kerneld to load the correct driver depending on the application.
-
-
-
-vy 73s de
-Tom Sailer, sailer@ife.ee.ethz.ch
-hb9jnx @ hb9w.ampr.org