Software based CLIP decoder


Simple ald low-cost CLIP (Calling Line Identification Presentation) decoder, which decodes caller number coded with V.23 protocol (FSK modulation), and shows it on LCD display. Device is based on simple AVR '2313 microcontroller and is an example, how to decode caller ID in a software manner. Here's short overview of V.23 coding:

Block diagram of CLIP decoder:

CLIP decoder features

CLIP coding V.23 (FSK modulation)
Input Analogue phone line
Output LCD (HD44780)
CPU AVR ('2313)
Supply voltage 15...20 VDC


CLIP decoder firmware (6.66kB)
Source code (written in C) shows how to decode CLIP signal coded with V.23 FSK protocol using only simple AVR microcontroller and simple analog front.

Schematic diagram (PDF) (17.36kB)

Project developed in 2004.