AT&T Callmaster Series Reference Manual page 59

External Ringing Tones
The following external ringing tone patterns are generated by the system:
RINGING TONE
For most currently available voice terminals, the user can select a Personalized Ringing pattern
(out of eight possible ringing patterns). The tone patterns are the same as those previously
described. The three tones are 530 Hz [low (L)], 750 Hz [medium (M)], and 1060 Hz [high (H)].
The tone sequences are as follows: (Each of these sequences is prefaced by a medium level
tone.)
1 1200 on, 4000 off; repeated
2 400 on, 200 off, 600 on, 4000 off; repeated
3 200 on, 100 off, 200 on, 100 off, 600 on,
4000 off; repeated.
RING PATTERN
1
2
3
4
5
6
7
8
GENERAL INFORMATION
PATTERN (In ms)
TONE SEQUENCE
MMM
HHH
LLL
LHH
HHL
HLL
HLH
LHL
2-19