Nortel DMS-100 Series General Description Manual page 23

The frequencies used in the frequency selective ringing scheme are as follows:
• harmonic ringing: 16-2/3 Hz, 25 Hz, 33-1/3 Hz, 50 Hz, 66-2/3 Hz
• synchromonic ringing (20 Hz base): 20 Hz, 30 Hz, 42 Hz, 54 Hz, 66 Hz
• synchromonic ringing (16 Hz base): 16-2/3 Hz, 30 Hz, 42 Hz, 54 Hz
• decimonic ringing: 20 Hz, 30 Hz, 40 Hz, 50 Hz, 60 Hz.
Frequency selective ringing is used by Rural Electrification Association
(REA) offices. The following figures illustrate the REA frequency selective
ringing timing for the following types of ringing:
• synchromonic
• harmonic
• decimonic
Synchromonic ringing
The following figure illustrates the relationship between the synchromonic
ringing signals and the DMS-100 ringing cycle.
Figure 1-4 Synchromonic ringing
0
FrequencyA 3 3 0 0 H H z z
(1 party)
1 1 . . 9 9 5 5 s s
(seenote)
FrequencyB
FrequencyC
FrequencyD
ANI/coin
(Any available slot)
0
Note: Available frequencies are 16-2/3 Hz, 20 Hz, 30 Hz, 42 Hz, 54 Hz and
66 Hz. Any four of the available six frequencies, in any order, can be
assigned to frequencies A through D: however, 16 Hz and 20 Hz can not be
used simultaneously.
1 2 3 4
4 4 2 2 H H z z
1 1 . . 3 3 5 5 s s
1 2 3 4
DMS-100 Family DMS-100 Ringing System BASE15 and up
DMS-100 ringing overview 1-7
6 s
5 6 7 8
5 5 4 4 H H z z
1 1 . . 3 3 5 5 s s
5 6 7 8 9
9 10 11
6 6 6 6 H H z z
1 1 . . 3 3 5 5 s s
10 11