36 CHAPTER 5: USING THE MODEM
S21 Bit-mapped. Storable. Bit 0: Telephone Jack (&J CMD)
■ 0 = RJ11
■ 1 = RJ12
Bit 1. IF DRS Follows DCD:
■ 0 = DSR as per bit 6.
■ 1 = DSR follows DCD all the time.
Bit 2. CTS control (&R CMD)
■ 0 = CTS follows RTS
■ 1 = CTS always on
Bit 4,3. DTR control (&D CMD)
■ 0 = Ignore DTR
■ 1 = Command state
■ 2 = Hang up
■ 3 = Reset
Bit 5. DCD control (&C CMD)
■ 0 = DCD always on
■ 1 = DCD controlled by modem
Bit 6. DSR control (&S CMD)
■ 0 = DSR always on
■ 1 = DSR controlled by modem
Bit 7. Long space disconnect (Y CMD)
■ 0 = Disabled
■ 1 = Enabled
S22 Bit-mapped. Storable.
Bit 1,0. Speaker volume control (L CMD)
■ 0=Low
■ 1=Low
■ 2=Medium
■ 3=High
Bit 3,2. Speaker control (M CMD).
■ 0=Always off
■ 1=On until carrier detected
■ 2=Always on when off hook
■ 3=Off during dialing and after carrier detected.
Bit 6,5,4. Extended response codes (X CMD)
■ 0 = Ignore GSTN status and do not report connection speed - (X0)
■ 1 = Detect busy and ringing tones and report connection speed - (X5)
■ 2 = As for X5 and also detect dial tone and perform adaptive dialing - (X6)
■ 3 = As for X6 - (X7)
■ 4 = As for X0 and also report connection speed - (X1)
■ 5 = Detect dial tone and report connection speed - (X2)
■ 6 = Detect busy tone and report connection speed - (X3)
■ 7 = Detect dial and busy tones and report connection speed - (X4)
Bit 7. Make/break ratio for pulse dialing (&P CMD). 0= S (39%/61%). 1=UK
(33%/67%)
