April 21, 1999 ISDNTELCTL 8

### NAME

isdntelctl - control isdn4bsd telephone sound format conversion

### SYNOPSIS

isdntelctl [-c] [-g] [-u unit] [-A] [-U] [-N]

### DESCRIPTION

isdntelctl is part of the isdn4bsd package and is used to configure the sound format conversion facilities of the /dev/isdntel interfaces.

The following options are available:

-c
  Clear the telephone input queue.

-g
  Get the sound format currently in use.

-u
  Set the ```/dev/isdntel` unit number. The default value is zero to access device ```/dev/isdntel0`.

-A
  Do A-law (ISDN line) -> mu-law (userland) conversion.

-U
  Do mu-law (ISDN line) -> A-law (userland) conversion.

-N
  Set sound conversion to do no format conversion.

The telephony data stream comes out of the line in a bit-reversed format, so the isdntel(4) driver does the bit-reversion process in any case.

Additionally, the user can specify to do A-law to mu-law, mu-law to A-law or no conversion at all in the isdntel driver by using the isdntelctl utility.

### FILES

```/dev/isdntel<n>`

### EXAMPLES

The command

  `

      isdntelctl -g

  `

displays the currently used sound format for device ```/dev/isdntel0`.

### SEE ALSO

isdntel(4), isdnd.rc(5), isdnd(8)

### STANDARDS

A-law and mu-law are specified in ITU Recommendation G.711.

### AUTHORS

The isdntelctl utility and this man page were written by Hellmuth Michaelis <hm@kts.org>
.