TRANSMIT CARRIER FREQUENCIES
V.22 bis:
V.22:
212A:
ORIGINATE
1200
Hz
+/-
0.01%
ANSWER
2400
Hz
+/-
0.01%
V.21 @ 300 bps:
ORIGINATE ‘ space’
1180 Hz +/- 0.01%
ORIGINATE ‘ mark’
980 Hz +/- 0.01%
ANSWER ‘ space’
1850 Hz +/- 0.01%
ANSWER ‘ mark’
1650 Hz +/- 0.01%
Bell 103:
ORIGINATE ‘ space’
1070 Hz +/- 0.01%
ORIGINATE ‘ mark’
1270 Hz +/- 0.01%
ANSWER ‘ space’
2020 Hz +/- 0.01%
ANSWER ‘ mark’
2225 Hz +/- 0.01%
LINE EQUALIZATION
(a) Fixed compromise equalization in transmitter
(b) Adaptive equalizer for 1200 and 2400 bps in receiver
INTERFACE SIGNALS
RS232C levels with CCITT V.24 protocols
AUTODIALER TYPE
DTMF or pulse type dialing, specified in commands
DTMF TONE PAIR BALANCE
Better than 3dB
DTMF TONE DURATION AND SPACING
Variable from 50 to 255 milliseconds (Register S11)
Default duration 100 milliseconds
PULSE DIALING RATE
10 pulses per second
PULSE DIALING DUTY CYCLE
39/61% (US) or 33/67% (UK Hong Kong) make/break ratio
PULSE DIALING INTERDIGIT INTERVAL
650 milliseconds
BILLING DELAY INTERVAL
2 seconds silent time, before answer tone