General description

This is a library containing common/shared code regarding the A-bis interface between BTS and BSC.
It implements drivers for mISDN and DAHDI based E1 cards, as well as some A-bis/IP dialects.


To compile libosmo-abis you will need the following tools:

sudo apt-get install build-essential libtool libortp-dev dahdi-source libsctp-dev shtool autoconf automake git-core pkg-config make gcc

Obtaining it

To obtain libosmo-abis, you can use the following git URL:

git clone git://

Compiling and installing it

To compile and install it as standalone:

cd libosmo-abis/
autoreconf -i
sudo make install
sudo ldconfig -i
cd ..


This library is GPL licensed. This means you *cannot use this library from non-GPL licensed code without infringing copyright!

Browsing its source code

You can do that using our cgit installation at

Input Drivers

There are currently the following input drivers available:


This input driver supports the mISDN code as it is present in mainline linux-2.6 kernels.

It uses the in-kernel LAPD implementation, and is thus bound to some restrictions. Specifically,
you can only have one signalling timeslot (D-channel) in every E1 line, which may cause problems
with multi-BTS or multi-TRX setups (particularly in the case of Nokia A-bis)

You have to configure which E1 timeslot is to be used for signalling by module parameters, e.g.

modprobe hfcmulti dslot=1

will configure TS1 as signalling.


This input driver supports the mISDN code as it is present in mainline linux-2.6 kernels.
However, unlike the "misdn" driver, it runs LAPD in userspace, as part of libosmo-abis.

In order to be able to use it, you will need to make sure the mISDN kernel driver does not
configure any timeslot to signalling, e.g.

modprobe hfcmulti dslot=-1

(notice the "-" in front of 1 to indicate "no signalling timeslot").


This driver supports the DAHDI (formerly known as zaptel) out-of-tree drivers for e.g.
the various Digium and Digium compatible E1/T1/J1 cards.


This implements A-bis over IP, as implemented by ip.access nanoBTS as well as all BTSs running OsmoBTS.


Experimental driver for support of the [HSL_Femto]


This driver supports osmo-e1d, the software-defined E1 inplementation of Osmocom.

osmo-e1d in turn supports the Osmocom open hardware ICE40 FPGA core, as well as virtual E1 loops for testing (vpair).

You must build with ./configure --enable-e1d to support this driver

Commercial Support

Commercial support as well as development, system integration and training services for this project are available from sysmocom

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