Signaling, Tones, and Transmission
United Kingdom
Tone Plan
Tone
Frequency
(Hz)
Cadence (s)
ARS 2nd Dial 350/440 Continuous
Busy 400 0.35 on, 0.35 off, repeat
Camp-on 400 0.1 on, off
Conference 400 0.1 on, off
Confirmation 350/440 Continuous
Dial 350/440 Continuous
Feature Active Dial 350/440 0.75 on, 0.75 off, repeat
Interrupted 1400 0.1 on, off
Message Notification 350/440 350/440 (0.75 on, 0.75 off) x 2, then 440 (0.1 on, 0.75 off), then 350/440 (0.75 on,
0.75 off, repeat)
Modem Answer 2025 0.95 on, 0.05 off, repeat
Number Unobtainable 400 Continuous
Paging 440 0.2 on, off
Ringing (Internal) 400/450 1 on, 2 off, repeat
Special Busy 400 0.35 on, 0.35 off, repeat
Special Ringing
(External)
400/450 0.4 on, 0.2 of, 0.4 on, 2 off, repeat
Transfer Dial 350/440 0.75 on, 0.75 off, repeat
Interrupted Dial 350/440 0.75 on, 0.75 off, repeat
Voice Mail 440 0.6 on, off
Tone
Output Level (in dBm)
iONS
abONS
ONS iOPS OPS
iACO
abACO
abACOhl
iACOs ACO ACOs DCO ATT
ARS 2nd Dial -8
-12
-17
-22
-7
-11
-16
-21
--- -10
-14
-19
-24
-4
-8
-13
-18
-3
-7
-12
-17
-4
-8
-13
-18
-4
-8
-13
-18
-5
-9
-14
-19
-4
-8
-13
-18
Busy -9
-14
-19
-8
-13
-18
--- -11
-16
-21
-5
-10
-15
-4
-9
-14
-5
-10
-15
-5
-10
-15
-6
-11
-16
-5
-10
-15
Dial -8
-12
-17
-22
-7
-11
-16
-21
---
-10
-14
-19
-24
-4
-8
-13
-18
-3
-7
-12
-17
-4
-8
-13
-18
-4
-8
-13
-18
-5
-9
-14
-19
-4
-8
-13
-18
Camp-on -9
-14
-19
-8
-13
-18
--- -11
-16
-21
-5
-10
-15
-4
-9
-14
-5
-10
-15
-5
-10
-15
-6
-11
-16
-5
-10
-15
Conference -14 -13 --- -16 -10 -9 -10 -10 -11 -10
Confirmation -8
-12
-17
-22
-7
-11
-16
-21
---
-10
-14
-19
-24
-4
-8
-13
-18
-3
-7
-12
-17
-4
-8
-13
-18
-4
-8
-13
-18
-5
-9
-14
-19
-4
-8
-13
-18