ePanorama telecom documents


Telephone line audio interface circuits

This document describes how telephone works and how you cain interface to telephone line. This document describes also telephone line technical details.

ADSL filters explained

This document describes how ADSL filters work and why they are needed.

Telephone ringing circuits

This document describes telephoen line ring signal details, and gives circuit ideas how to generate and detect telephone rign signals.

Caller ID circuits

Information about caller identification circuits

Bellcore Caller ID specification

Bellcore Caller ID specification

Caller ID system used in Finland

Information about coils

Fax to Modem interface

Fax to Modem interface

Gyrator circuit: simulate large coils electronically

Sometimes coils with large inductance is needed in telecommunication systems and filters. Coils with inductance of many henries are not usually very useful in modern small electronics circuits. To overcome there is one solution which can be used in many applications: simulate the behauvior of coils using electronics.

Use old phones as an intercom

Very simple intercom circuit

How to record telephone conversations

How to record telephone conversations

Telephone line surge protection

Telephone line surge protection

Telephone wiring in UK

Telephone wiring in UK

u-LAW and A-LAW definitions

u-LAW and A-LAW definitions

Generating DTMF tones using soundcard

What are DTMF tones and how to generate then using software algoriths.