AXE telephone exchange

The AXE telephone exchange is a product line of circuit switched digital telephone exchanges manufactured by Ericsson, a Swedish telecom company.

The AXE is the digital successor to the AKE analogue telephone exchange and ARF/ARM family of crossbar switches. The design is modular with an APZ dual processor running in sync mode, an APT switching part and an APG I/O part. It is used to connect local landlines, operate mobile networks (TDMA, GSM, CDMA, W-CDMA, PDC), international telephony traffic and signaling.

The brain of the AXE system is a dual processor system called APZ. It runs in parallel sync mode making it fault redundant. The family of APZs started with APZ 210 03 back in 1976 and the latest one is APZ 212 55. The parallel sync mode was partly abandoned in the APZ 212 40 and onwards being replaced with a warm standby scheme.

The core of the switching part was the Group Switch, initially a time-space-time multiplexer capable of switching up to 64K positions or connections. This Group Switch later evolved to a Distributed Group Switch using Time-Space switching technique with a maximum capacity of 512K.

Ericsson AXE telephone exchanges support lawful intercepts via the remote-control equipment subsystem (RES), which carries out the tap, and the interception management system (IMS), software used to initiate the tap which adds the tap to the RES database. In a fully operating lawful interception system the RES and IMS both create logs of all numbers being tapped so that system administrators can perform audits to find unauthorized taps.

Code is written in PLEX, SDL and ASA210C programming languages. Code for Regional Processors (controlling hardware Extension Modules) is written in ASA210R.

Terminology

APG

Adjunct Processor Group

DT

Data Transcript

IOG

Input-Output Group

See also

• Greek telephone tapping case 2004-2005

External links

• Ericsson AXE web page