AN1500A South African Micro-Electronic Systems, AN1500A Datasheet - Page 5

Manufacturer Part Number

AN1500A

Description

Single Chip Telephone Demo Board

Manufacturer

South African Micro-Electronic Systems

Datasheet

1.AN1500A.pdf (27 pages)

6 General Description

The SA2532K device was developed to provide “plug & play” solution for the Indian DOT, emphasizing high

performance voice transmission and reception. In spite of the fact that voice transmission and reception are the

most vital features in telephony, they are very often ignored or given lower priority compared with some more or

less useless non-voice features. No compromises were accepted during the design phase of the SA2532K, which

is based on the SA2531/2 speech circuit and which supersedes even the hardest PTT requirements worldwide.

The dialler part is based on a long history of producing a wide range of dialer circuits with user-friendly features in

compliance with various national PTT regulations. This knowledge enabled us to develop a specific product to meet

with DOT type approval.

The last piece in the puzzle to complete the full picture of the first CMOS single chip POT was the tone ringer. A

ring frequency discrimination circuit was implemented to avoid false “bell-tinkle” during pulse dialing from a parallel

telephone. The 3-tone melody generator provides the ringing signal.

Note: all the subsequent component numbering is referenced to the AN1500 schematic, shown in pt.22

7 Demo board configuration

The SA2532K is the rare combination of advanced technology and down-to-earth simplicity providing easy and

uncomplicated design effort for the telephone manufacturer. No fussing around: Simply go by the straight forward

guidelines supplied by a highly experienced application group. No technology stress but appealing functionality.

See Fig. 1 for configuration locations:

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J3: line loss compensation

selector

AN1500A

Ringer Capsule

Connector

J1 :Line terminal selection

Line connector

sames

Fig. 1: Demo board configuration

Sidetone Network

J2: Dial Mode

Selection

Handset Connector