Description

ST9S424-PG16 is a line interface designed to implement Modem application up to 56Kbps and Voice applications. It interfaces between telephone line and capacitive isolation barrier. A complete D.A.A. is made with ST75951 which interfaces between capacitive isolation barrier and the DSP or HSP signals. If CLID external transistor switch is enabled, a limited amount of current, less than 1mA, is drawn from the line. In off-hook state, ST9S424-PG16 DC voltage, 4V at a 20mA line current, allows to interface with most of public networks in the world. The return loss is externally adjustable to real or complex impedance. In case of a wrong connection in a digital phone line, ST9S424-PG16 detects the over current value and sends to ST75951 an alert signal through the capacitive isolation barrier. Before starting a line connection, ST9S424-PG16 is abled to check if the line is used by an other terminal connected on the same telephone line.

Specifications and features

■ HOOK SWITCH DRIVER
■ RING INDICATOR
■ LINE INTERFACE
- DC TERMINATION (4V AT 20mA)
- 2W/4W HYBRID CONVERTER
- FLAT FREQUENCY RESPONSE DOWN TO 10Hz FOR 56Kps MODEM
■ INTERFACE WITH CAPACITIVE ISOLATION BARRIER
■ CALLER ID INTERFACE
■ DIGITAL PHONE LINE OR OVER LOOP CURRENT LIMIT DETECT
■ PHONE LINE IN USE CHECK

Application Scenarios

■ MODEMS UP TO V.34, 33.6KBPS AND 56Kbps
■ PCMCIA CARDS
■ FAX MACHINES
■ PERSONAL DIGITAL ASSISTANTS
■ ANSWERING MACHINES
■ HIGH FEATURE PHONES
■ WEBPHONES AND SET TOP BOXES