Compaq Armada 1700 Reference Manual page 87

S89
S90
S32
S33
The modem alerts the DTE to the presence of tones detected on
the phone line. During a voice call, the modem is capable of
simultaneously detecting tones other than voice. When such a tone
is detected, the modem responds via the communications interface
with one of the following response codes:
0-9, A-D,#,*
a
b
c
d
e
h
H
R
r
s
@
Continued
Sleep Mode Timer.
Read-only Local Phone.
Synthetic Ring Volume.
Synthetic Ring Frequency.
DTMF Tones
Answer Tone
Busy Tone
Fax Calling Tone
Dial Tone
Data Calling Tone
Local Phone On-Hook
Local Phone Off-Hook
Ring
Ringback
Silence Timer Has Expired
CAS Tone Detected