V22 and Bell 212A Modem

CMX644A

© 2000 Consumer Microcircuits Limited

2

D/644A/6

CONTENTS

Section

Page

1.1

Brief Description ..................................................................................1

1.2

Block Diagram......................................................................................3

1.3

Signal List ............................................................................................4

1.4

External Components ..........................................................................6

1.5

General Description .............................................................................7

1.5.1

‘C-BUS’ Interface .....................................................................7

1.5.2

UART .......................................................................................8

1.5.3

Software Description.............................................................10

1.6

Application Notes ..............................................................................21

1.6.1

Line Interface .........................................................................21

1.6.2

Ring Detector Interface .........................................................23

1.6.3

Software Protocol for Transmitting PSK Data Bytes...........24

1.6.4

Software Protocol for Receiving PSK Data Bytes ...............25

1.6.5

Handling Underflow and Overflow Conditions....................25

1.7

Performance Specification ................................................................27

1.7.1

Electrical Performance..........................................................27

1.7.2

Packaging ..............................................................................32