ttyI, cui - ISDN character devices with modem emulator
DESCRIPTION
ttyI[0-63] and cui[0-63] are emulated tty devices of the
Linux ISDN subsystem. These devices can be used in the
same way as the traditional serial devices ttySx and cuax.
The official major device numbers are 43 for ttyI and 44
for cui. The minor device numbers start with 0 and end
with 63.
The ISDN tty devices are equipped with a modem emulation
implementing a set of traditional and some special AT com
mands. This provides easy use together with almost all
communication software that uses modem commands: mini
com(1), seyon(1), XCept(1), uucico(8), mgetty(8), dip(8),
pppd(8) and more. When enabled during kernel configura
tion, the emulator is capable of a reduced set of commands
to support audio. To use audio features, an ISDN card with
a audio-capable low-level driver is needed. Currently the
only audio-capable drivers are the teles and HiSax driver.
The line disciplines are handled by the kernel so that
SLIP, CSLIP and asynchronous PPP are possible.
The port speed of the ISDN tty devices is always 64000
bps.
AT COMMAND SET
The description of AT commands here does not cover audio
related commands. For a description of audio related com
mands, see isdn_audio(4). The following AT commands are
supported by ISDN tty devices:
ATA Answer an incoming call.
ATDnum Dial number num. Allowed are digits [0-9] and the
characters ",", "#", ".", "*", "W", "P", "T", "S",
"-". The characters are ignored except of "S" which
indicates a SPV if it precedes the number (only
German 1TR6 ISDN).
ATE0 Echo off.
ATE1 Echo on (default).
ATH Hang up.
ATH0 Hang up.
ATH1 Off hook (ignored).
ATI1 Return device Information ("ISDN for Linux...").
ATI2 Return Statistics of last connection.
ATO Return from command mode to online mode (data
mode).
ATQ0 Enable result codes (default).
ATQ1 Disable result codes.
ATSx=y Set register x to value y.
ATSx? Show content of register x.
ATSx.y=z
Set register x, bit y to value z
ATSx.y?
Show bit y of register x.
ATV0 Print result code as number.
ATV1 Print result code as text (default).
ATZ Reset all registers and load profile values.
AT&Bx Set packet size of outgoing packets to value x
(maximum 4000). The actual packet size depends on
the hardware driver and may be smaller than x (e.g.
with the teles driver). There will be no error mes
sage if the value is bigger than the hardware
driver can process. However the size of the outgo
ing packets will be set correctly.
AT&D2 DTR falling edge: hang up and return to command
mode (default).
AT&D3 DTR falling edge: hang up, return to command mode
and reset all registers.
AT&Ex Set MSN (Euro-ISDN, EDSS1) or EAZ (German 1TR6) to
value x. For MSNs, x is a string of digits repre
senting the local phone number, while for EAZs x
should be only the last digit of the Number.
AT&F Set all registers and profile to "factory-
defaults".
AT&V Show current register settings.
AT&X0 Disable BTX-Mode (default).
AT&X1 Enable BTX-Mode.
ESCAPE SEQUENCE
During a data connection, the driver can be set to command
mode by typing in delay+++delay. The escape character
(default "+") may be set via register 2. The delay must be
at least 1.5 seconds and between each escape character the
pause must not exceed 0.5 seconds. ATO brings the modem
emulation back to data mode.
REGISTERS
0 (default 0)
Number of rings on which the "modem" will answer.
(S0=0 will disable auto answering).
1 (default 0)
Counts and stores the number of rings from an
incoming call.
2 (default 43 = '+')
ASCII code of the escape character.
3 (default 13 = CR)
ASCII code of Carriage Return.
4 (default 10 = LF)
ASCII code of Line Feed.
5 (default 8 = BS)
ASCII code of Backspace.
6 (default 3)
Duration, in number of seconds, modem waits before
dialling.
7 (default 60)
Wait time for carrier in seconds (ignored).
8 (default 2)
Pause time for comma (',') in dial command in sec
onds (ignored).
9 (default 6)
Carrier detect time in tenths of seconds (ignored).
10 (default 7)
Wait time until hangup after carrier loss in tenths
of seconds (ignored).
Duration and delay in milliseconds for touch tone
dialling (ignored).
12 (default 69)
Bit-mapped register.
Bit Description
0 0 = Suppress response messages.
1 = Show response messages.
1 0 = Response messages as text.
1 = Numeric response messages.
2 0 = Echo off.
1 = Echo on.
3 0 = DCD always on.
1 = DCD follows carrier.
4 0 = CTS follows RTS.
1 = Ignore RTS, CTS always on.
5 0 = Low-edge on DTR: Hangup and return
to command mode.
1 = Same as 0 but also resets all
registers.
6 0 = DSR always on.
1 = DSR on only if channel is available.
7 0 = Cisco-PPP-flag-hack off.
1 = Cisco-PPP-flag-hack on.
13 (default 4)
Bit-mapped register.
Bit Description
0 0 = Use delayed sending of data.
1 = Immediately send data.
1 0 = T.70 protocol off.
1 = T.70 protocol on.
2 0 = Don't hangup on DTR low.
1 = Hangup on DTR low.
3 0 = Standard response messages.
1 = Extended response messages.
4 0 = CALLER NUMBER before every RING.
1 = CALLER NUMBER after first RING.
14 (default 0)
Layer-2 protocol.
0 = X75/LAPB with I-frames.
1 = X75/LAPB with UI-frames.
2 = X75/LAPB with BUI-frames.
3 = HDLC.
4 = TRANSPARENT.
15 (default 0)
Layer-3 protocol.
0 = transparent
16 (default 250)
18 (default 4)
Service-Octet-1 to accept or to be used on dial
out.
Bit-mapped register.
Bit Description
0 Service 1 (audio) when set.
1 Service 5 (BTX) when set.
2 Service 7 (data) when set.
Note: It is possible to set more than one bit. In
this case, on outgoing calls, the most sig
nificant 1-bit is chosen to select the out
going service octet. On incoming calls the
selected services are accepted, contents of
register 14 is ignored and the Layer-2-pro
tocol is automatically set with the follow
ing values to match the service of the
incoming call:
Incoming service audio (Reg. 20.0 = 1)
L2-protocol is set to 4 (TRANSPAR
ENT).
Incoming service BTX (Reg. 20.1 = 1)
L2-protocol is set to 0 (X75/LAPB
with I-frames).
Incoming service date (Reg. 20.2 = 1)
L2-protocol is set to 0 (X75/LAPB
with I-frames).
19 (default 0)
Service-Octet-2 (ignored when using EDSS1).
20 (read only)
Service-Octet-1 of last incoming call. This bit-
mapped register is set on incoming call (during
RING). Mapping is the same like register 18.
21 (read only)
Bit-mapped register. Set on incoming call (during
RING) to the value of octet 3 of calling party num
ber Information Element (Numbering plan). See sec
tion 4.5.10 of ITU Q.931.
22 (read only)
Bit-mapped register. Set on incoming call (during
RING) to the value of octet 3a of calling party
number Information Element (Screening info). See
section 4.5.10 of ITU Q.931.
Fritz Elfert <fritz@wuemaus.franken.de>
SEE ALSO
icnctrl(8), telesctrl(8), isdninfo(4), isdn_audio(4), isd
nctrl(8).
