1SETHDLC(8) Linux Programmer's Manual SETHDLC(8)
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6 sethdlc - get/set Linux HDLC packet radio modem driver port information
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9 sethdlc [ -bdhs ] [-i device]
10 sethdlc [-i device] -c cal
12 sethdlc -p [-i device] [ mode mode ] [ io iobase ] [ irq irq ]
14 [ dma dma ] [ dma2 dma2 ] [ serio seriobase ] [ pario pariobase ]
15 [ midiio midiiobase ] [ options options ]
16 sethdlc -a [-i device] [ txd txdelay ] [ txtail txtail ] [ slot slot‐
18 time ] [ ppersist ppersistence ] [ full ] [ half ]
19
23 sethdlc is a program designed to set and/or report the configuration
24 information associated with a soundcard radio modem port. This infor‐
25 mation includes the modem type, what I/O port, IRQ and DMA channel a
26 particular modem port is using, and where to output a transmitter key‐
27 ing (PTT) signal.
28 With the -p option, sethdlc sets and/or reports the port configuration.
30 With the -a option, sethdlc sets and/or reports the AX.25 channel
32 access parameters. These parameters can also be set with the kissparms
33 utility.
34 With the -c option, sethdlc instructs the driver to send a calibration
36 pattern for cal seconds.
37 Without the -p, -a and -c option, sethdlc will stay in the foreground
39 and display received packets. The AX.25 header and eventually a FlexNet
40 compressed header are decoded. CTRL-C terminates sethdlc. Specifying
41 additional options, sethdlc may display additional information.
42
46 sethdlc accepts the following options:
47 -b Trace the bits at the output of the demodulator, after RX clock
50 recovery. This option is only available if sethdlc and the
51 soundcard modem kernel driver is compiled with debugging support
52 on. This is useful for driver debugging.
53 -d Trace DCD, PTT and other status information on stdout. sethdlc
55 displays two times per second a line containing these informa‐
56 tions.
57 -h Display an overview of the available command line parameters and
59 exit.
60 -i The device argument specifies the HDLC modem device which should
62 be configured or interrogated. It will usually have the follow‐
63 ing form: bc[0-3] for the baycom driver and sm[0-3] for the
64 soundcard modem driver.
65 -s Trace the bits at the demodulator output, before the RX clock
67 recovery, to stdout. This option is only available the modem
68 driver is compiled with debugging support on. It may not be
69 available on some modem, such as the par96.
70
73 The following parameters can be assigned to a soundcard radio modem
74 port.
75 All numerical parameter values are assumed to be in decimal unless pre‐
77 ceeded by "0x".
78 The mode parameter sets the type of hardware and the operating mode of
80 the driver. ser12 and par96 are valid modes for the baycom driver. A
81 star "*" may be added to enable software DCD. The mode string format of
82 the soundmodem driver is as follows: hw:mode. hw may be either sbc,
83 wss or wssfdx. The first one specifies SoundBlaster compatible sound‐
84 cards, the second one WindowsSoundSystem compatible hardware, and the
85 third one WSS fullduplex operation (which currently works with Crystal
86 Semiconductor Chipsets CS423[126]). The mode portion may be afsk1200 or
87 fsk9600. Optionally, the receive and transmit modes may be different
88 (hw:txmode.rxmode).
89 The ioport parameter sets the I/O port address. Typical values for the
91 ser12 modem are 0x3f8, 0x2f8, 0x3e8 or 0x2e8, for the par96 modem
92 0x378, 0x278 or 0x3bc, for the sbc modems 0x220 and for the wss modems
93 0x530, 0x608, 0xe80 or 0xf40.
94 The irq parameter sets the hardware IRQ number. Typical values for the
96 ser12 modem are 4 and 3, for the par96 modem 7 or 5, for the sbc modems
97 are 7 or 5 and for the wss modems, any free IRQ from the set 2, 7, 9,
98 10, 11 will do. The driver automatically configures the WSS soundcard
99 to the correct IRQ.
100 The dma parameter sets the hardware DMA number. Typical values for the
102 sbc modems are 1 or 0 and for the wss modems, any free DMA from 0 to 3
103 (except 2) will do. The driver automatically configures the WSS sound‐
104 card to the correct DMA. The Baycom modems do not need DMA.
105 The dma2 parameter sets the second hardware DMA number. This is only
107 needed for full duplex operation with the soundmodem driver.
108 The seriobase parameter optionally sets the address of a serial port,
110 where the driver will output a PTT signal at the TxD and RTS pins, and
111 a DCD signal at the DTR pin. As Baycom modems do have their own PTT
112 pin, this parameter is not used by the Baycom modem driver.
113 The pariobase parameter optionally sets the address of a LPT port where
115 the driver will output a PTT signal on the DATA0 line and a DCD signal
116 on the DATA1 line. As Baycom modems do have their own PTT pin, this
117 parameter is not used by the Baycom modem driver.
118 The midiiobase parameter optionally sets the address of a MPU401 com‐
120 patible MIDI port, where the driver will output a PTT signal. Since the
121 MIDI port is effectively an UART and therefore cannot output a DC sig‐
122 nal, the output must be fed through a retriggerable monoflop with a
123 period of about 15ms. See
124 http://www.ife.ee.ethz.ch/~sailer/pcf/ptt_circ/ptt.html for a sample
125 schematic diagram. As Baycom modems do have their own PTT pin, this
126 parameter is not used by the Baycom modem driver.
127 The txdelay sets the transmitter keyup delay time. Unlike kissparms,
129 the unit is tens of ms. This is the time the transmitter needs to
130 switch its PA on and for its frequency synthesizer to settle. Typical
131 values for a handheld transceiver are 200ms (i.e. 20), and for a good
132 crystal driven transceiver 20ms (i.e. 2).
133 The txtail sets the time PTT is held after the last packet. Unlike
135 kissparms, the unit is tens of ms. Do not set this value to 0. Most
136 modems need some extra time to actually clock the last bits out to the
137 transmitter.
138 The slottime parameter specifies how often the channel access algorithm
140 is executed. Unlike kissparms, the unit is tens of ms. Unless you have
141 very specific requirements, set this to 100ms (i.e. 10).
142 The ppersist sets how "eagerly" the station starts to transmit as soon
144 as the channel gets free. The optimum value is 256 divided by the num‐
145 ber of stations on the channel. (This should really be done automati‐
146 cally by the L2)
147 full sets the modem to full duplex mode. Note that some modems do not
149 actually support full duplex mode, in this case this parameter makes
150 the modem start its transmission as soon as it gets packets from the
151 upper layer, without waiting for the channel to become free. This is
152 needed by some implementations of alternative channel access algo‐
153 rithms, e.g. DAMA.
154 half sets the modem to half duplex mode.
156
159 It is important to note that sethdlc merely tells the Linux kernel
160 where it should expect to find the I/O port and IRQ lines of a particu‐
161 lar serial port. It does not configure the hardware to use a particu‐
162 lar I/O port. In order to do that, you will need to physically program
163 the serial board, usually by setting some jumpers or by switching some
164 DIP switches.
165 This section will provide some pointers in helping you decide how you
167 would like to configure your baycom ports.
168 The "standard MS-DOS" port associations are given below:
170 COM1, port 0x3f8, irq 4
172 COM2, port 0x2f8, irq 3
173 COM3, port 0x3e8, irq 4
174 COM4, port 0x2e8, irq 3
175 LPT1, port 0x378, irq 7
176 LPT1 (on hercules graphics adapter), port 0x3bc, irq 7
177 LPT1, port 0x278, irq 5
178
181 Some cards need to be initialized before they act as a WSS or Sound‐
182 Blaster compatible card. This driver does not do this. You can use the
183 standard linux sound driver, if compiled as a module. Just load the
184 sound driver (insmod sound) and remove it again (rmmod sound). The card
185 should then be configured for either soundblaster or WSS compatibility.
186 If this does not work for some reason, you'll have to write your own
187 soundcard configuration utility. This is not as complicated as it
188 sounds; it can be done from user space (but requiring root privileges)
189 using ioperm and/or iopl.
190 It is important that the audio levels of your radio match those of the
192 soundcard. To help achieve this, there are two utilities: smdiag and
193 smmixer. See their respective manpage.
194 The sound driver and the soundcard modem driver are mutually exclusive,
196 i.e. they cannot both access the same soundcard at the same time. Even
197 worse, the sound driver reserves the soundcard as soon as it gets
198 loaded. The souncard modem driver however reserves the card only when
199 the interface is started, i.e. during ifconfig sm[0-3] up.
200 9600 baud may not currently work on SoundBlaster cards with DSP revi‐
202 sion 4.x, i.e. SB16 and SB32 AWE. This is because they seem to not be
203 fully backwards compatible.
204
207 CAUTION: Using an invalid port can lock up your machine.
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211 smdiag (8), smmixer (8), kissparms (8),
212 linux/drivers/net/hdlcdrv.c,
213 linux/drivers/net/baycom.c,
214 linux/drivers/net/soundmodem.c
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218 sethdlc was written by Thomas Sailer, HB9JNX/AE4WA
219 (t.sailer@alumni.ethz.ch). Inspired by setserial.
220Sethdlc 0.1 1 October 1996 SETHDLC(8)