Option Register

S14 Bit mapped configuration register

Bit 0

Unused

 

 

 

Bit 1

0

Command echo disabled (E0)

 

1

Command echo enabled (default E1)

 

 

 

Bit 2

0

Result codes enabled (default Q0)

 

1

Result codes disabled (Q1)

 

 

 

Bit 3

0

Digit result codes (V0)

 

1

Word result codes (default V1)

 

 

Bit 4

Unused

Bit 5

0

Tone dial (T)

 

 

 

 

1

Pulse dial (default P)

 

 

Bit 6

Unused

Bit 7

0

Answer mode

 

1

Originate mode (default)

 

 

 

S21 Bit mapped configuration register

Bit 012

Unused

Bit 34

0 0

Modern ignores DTR (&D0)

 

01

On-to-Off transition on DTR causes the modem to go to the

 

 

command state (&D1)

 

10

On-to-Off transition on DTR cause the modem to hang up

 

 

(default &D2)

 

11

On-to-Off transition on DTR causes the modem to reset (&D3)

 

 

 

Bit 5

0

DCD always ON (&C0)

 

1

DCD tracts the actual state of the data carrier (default & C1)

Bit 6

Unused

 

 

 

Bit 7

0

Long Space Disconnect disabled (default Y0)

 

1

Long Space Disconnect enabled (Y1)

 

 

B-10 Fax/Modem