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       ttyI, cui - ISDN character devices with modem emulator


       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


       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

       ATQ0   Enable result codes (default).

       ATQ1   Disable result codes.

       ATSx=y Set register x to value y.

       ATSx?  Show content of register x.

              Set register x, bit y to value z

              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-

       AT&V   Show current register settings.

       AT&X0  Disable BTX-Mode (default).

       AT&X1  Enable BTX-Mode.


       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.


       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

       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
              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
              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

                      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>


       icnctrl(8), telesctrl(8), isdninfo(4), isdn_audio(4), isd­