           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).