beautypg.com

Multi-Tech Systems Modem Module MT3334SMI User Manual

Page 38

background image

ModemModule Developer’s Guide

MT3334SMI

38

Table 3-2. Single-Page Class 1 Transmit Example

Action by

Action by

Command

Respone

Local Modem

Remote PC

AT+FCLASS=1

OK

Set Class 1

ATD

Dial and send CNG

Answers

Look for V.21

Sends CED, V.21

Detect flags

Sends HDLC flags

CONNECT

Detect flags

Get CSI

Send CSI packet

Send NSF packet

OK

AT+FRH=3

CONNECT Detect flags

Get CSI

Send CSI packet

Get FCS

OK

Accept FCS

Check FCS

AT+FRH=3

CONNECT

Detect flags

frame data

Get DIS

Send DIS packet

Get CRC

OK

Accept FCS Check FCS

AT+FRH=3

NO CARRIER

Detect loss of carrier

Drop carrier

AT+FTH=3

Send V.21 carrier

Detect carrier

CONNECT

Send flags

Detect flags

Send TSI frame

Get TSI frame

Send FCS

CONNECT

Send flags

Send DCS frame

Send DCS frame

Send FCS, flags

OK

Drop carrier

AT+FTS=8; +FTM=96

Wait 80 msec

CONNECT

Send V.29 carrier

Detect carrier

Send TCF data

Get TCF data

OK

Drop carrier

AT+FRH=3

Detect carrier

Send V.21 carrier

CONNECT

Detect flags

Send flags

Get CFR frame

Send CFR frame

Check FCS

Send CRC

OK

Accept FCS

AT+FRH=3

NO CARRIER

Detect loss of carrier

Drop carrier

AT+FTM=96

CONNECT

Send V.29 carrier

Detect carrier

Send page data

Receive page

OK

Drop carrier

AT+FTS=8; +FTH=3

Wait 80 msec

Send V.21 carrier

Detects carrier

CONNECT

Send flags

Detects flags

Send EOP frame

Receives EOP

Send FCS

OK

Drop carrier

(Final frame)

AT+FRH=3

Detect carrier

Send V.21 carrier

CONNECT

Detect flags

Send flags

Get MCF frame

Send MCF frame

Check FCS Send FCS

OK

Accept FCS

AT+FRH=3

NO CARRIER

Detect carrier loss

Drop carrier

AT+FTH=3

Send V.21 carrier

Detects carrier

CONNECT

Send flags

Detect flags

Send DCN frame

Receives DCN

Send FCS

OK

Drop carrier

ATH0

OK

Hang up

Hangup