ANT is Not a Telephone


What's ANT?

ANT is a desktop ISDN telephony application written for GNU/Linux. It supports ALSA (sound system) and CAPI 2.0 (ISDN interface). Its user interface was made for GTK+ 2.x (GIMP toolkit).

It directly interfaces ALSA and CAPI devices, so there is no need to install extra software or hardware like PBX (Private Branch Exchange) or telephony cards, if you've got direct access to an CAPI telephony capable ISDN card (teles or HiSax chipset, e.g. AVM Fritz Card) and a full duplex soundcard or two sound devices.

NOTE: Currently, this is a work in progress (beta version) and may contain bugs. But for me, it runs quite stable now. So don't hesitate after looking at the rather small version number and try it out. Any comments, suggestions and bug reports are welcome.

Download tarball of current version here: ant-phone-0.2.1.tar.gz



Have a first look at ANT with this screen shot:


Also listen to vbn-stereo.ogg or vbn-stereo.wav to have an impression of the power of the recording feature in ANT. (Don't be frightened, it's recorded from the voice mailbox of - a serious company! :)

Supported Hardware

The following list isn't very exhaustive yet. :-) Please supply me with the vendor and product name of your ISDN card, if you successfully tested ANT with your card not mentioned in the following list. Basically, every ISDN card with CAPI 2.0 Linux drivers should be supported by ANT. Please give me the name of your driver if use a different one.

Supported Cards:



This software is delivered in different forms:

Please note that the operating system distribution specific packages (Debian, SuSE etc.) are sometimes a bit out of date. Besides, I don't personally support the OS distribution specific packages (except Debian). Please contact the respective maintainers when problems arise.

After downloading the source tarball, just unpack it, build (compile) and install the executable and run it:
tar xfvz ant-phone-X.X.X.tar.gz
cd ant-phone-X.X.X
make install


(Further documentation is included in the tarball.)


This program is free software and is covered by the GPL (GNU General Public License, Version 2), but could also be licensed in other ways by sponsors. Please contact me for that.


Before reporting bugs, please read the following Frequently Asked Questions and also refer to the Mailing List Archives if your problem was encountered before. Be prepared that I can't answer all these questions again and again.

Q: How do I report a bug?

A: After reading this FAQ, please write me an email containing:

  1. A description of the bug so that I can reproduce it
  2. A debug output from the program, created with:
    $ ant-phone --debug=2
  3. The kernel version number (and possibly the list of applied patches, if appropriate), e.g. 2.6.22
  4. The architecture you are running the program on, e.g. i386
  5. The name of your ISDN card, e.g. AVM Fritz! PCI II
  6. The name and driver of your sound card.

Q: On ./configure, I get complaints about missing libsndfile or gtk (but I installed it)

A: Try with the development files (headers), instead of only with the binary package. The headers are usually contained in <packagename>*-dev (for Debian) or <packagename>*-devel (for SuSE) or something like that. Note that you need libsndfile version 1.0 or above.

Q: I get an ISDN related error at startup.

A: Please make sure that:

  1. You have a supported ISDN card
  2. You have activated the ISDN specific options in your kernel, especially CONFIG_ISDN_AUDIO
  3. You belong to the group the /dev/capi20 device is associated with

Q: There's already another project called "ANT" (Java build tool).

A: I'm sorry that I noticed that too late. I have planned to release "my" ANT back in the end of 2000 and didn't check the whole web for namesakes. My compromise is to use the name ANT always in conjunction with "ANT is Not a Telephone" or as "ant-phone". As long as there are more people happy with my little project than complaints, I won't change the name. Besides, even in the FRG, there are many computer/IT related companies with the same name. We seem to have to arrange with each other. And fortunately, "Another Neat Tool" plays in a completely different category (league? ;).

Q: While a phone session is open (B-channel), the CPU consumption is high.

A: Upgrade to 0.2.0, which uses threads. This was a kernel-internal problem. While reading blocks from a kernel audio device (and ISDN), select(2) consumed much kernel CPU time.

How to contribute

Besides sponsoring :) there are some other ways to contribute to this project. Here, I've got some points from the TODO list which I definitely can't do myself in the near future for different reasons. If you like to take one, please write me an email. Thanks!


Any suggestions, comments and bug reports (which are highly appreciated) go to the ant-phone mailing list For discussion and announcements, you can subscribe to the list. You can also browse the Mailing List Archives. If this fails or for non-public discussion, contact the maintainer directly: Roland Stigge <>.

Created by on 2002-09-23