VII.2.7 - Default Optional Status in DTMF Receiver Mode

While in DTMF receiver mode the format of the STAOP word is as follows :

Add.

Name

Bit

765

4

321

0

$0C

STAOP0

TDT7

(1)

TDT6

(1)

TDT5

(1)

TDT4

(1)

TDT3

TDT2

TDT1

TDT0

$0D

STAOP1

TDT15

(1)

TDT14

(1)

TDT13

(1)

TDT12

(1 )

TDT11

(1)

TDT10

(1)

TDT9

(1)

TDT8

(1)

$0E

STAOP2

DTMF_DIGIT

(2)

Notes : 1. These cells are used by the DTMF detector.

2. DTMF_DIGIT is valid when the bit 7 of STATUS[1] (STA_DTMF) goes high. This value remains unchanged until a new DTMF

digit is detected.

VII.2.8 - Default Optional Status in Modem Mode

While in modem mode the format of the STAOP word is as follows :

Add.

Name

Bit

765

432

1

0

$0C

STAOP0

x

x

x

SPEED

(2)

SPVAL

(1)

$0D

STAOP1

Not used

$0E

STAOP2

PNSUCs

PRDETs

PNDETs

SCR1s

PRs

PNs

P2s

P1s

Notes : 1. SPVAL is active in V.33 receiver only at the same time as the rising transition of the SCR1s signal. Went SPVAL is set, it

indicates that the SPEED bits contain the data speed information.

2. SPEED is valid in V.33 receiver only. It can have 2 values, after the SCR1s signal goes high : 1000 for 14400bps and 0111 for

12000bps.

3. The STAOP2 bit reflects the progression of the synchronization. The STAOP2 bits have the following meaning :

Name

Position

Description

Tx

Rx

P1s

0

Unmodulated carrier sequence. Optional, used for echo protection.

X

P2s

1

Continuous 180

° phase reversal sequence

X

X

PNs

2

Equalizer trainning sequence

X

X

PRs

3

V.33 and V.17 rate sequence

X

SCR1s

4

Continuous scrambled 1 sequence

X

X

PNDETs

5

Turned on after PN sequence detection

X

PRDETs

6

Turned on after PR sequence detection (V.33 and V.17 only)

X

PNSUCs

7

Turned on after succesfull training of the receive equalizer. When on at

the end of the synchronization, the transmition BER is statisticaly

bellow 10ppm.

X

ST75C520

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