(1) Receiving Conditions:
Dial Speed: 9 ~ 11 pulses per second (pps)
Break Ratio: 55 ~ 77% (10 pps)
Minimum Inter-digital Pause: 192 ms
Switch Hook Flash Detection: 310 ~ 1610 ms a.
(2) Sending Conditions
Dial Speed: 10 pps (?0.8 pps)
Break Ratio: 67 ?3%
Minimum Inter-digit Pause: 800 ms
DTMF Signaling
(1) Receiving Conditions (Measured at Receiver Input)
Signal Duration: More than 40 ms
Inter-digital Pause: More than 40 ms
Signal Level: 0 ~ -25 dBm
(2) Sending Conditions
Signal Duration: More than 64 ms
Inter-digit Pause: More than 64 ms
Signal Level:
Low Frequency: -10 dBm
High Frequency: - 9 dBm
DTMF Frequencies
1209Hz
1336Hz
1477Hz
697Hz
1
2
3
770Hz
4
5
6
852Hz
7
8
9
941Hz
*
0
#
Audible Tones and Ringing Signal
Audible Tones
TONE
FREQUENCY
INTERRUPTION
Dial Tone (DT)
350 Hz mixed with 440 Hz
Continuous
Special Dial Tone (SDT)
350 Hz mixed with 440 Hz
0.125 sec. ON, 0.125 sec. OFF
Busy Tone (BT)
480 Hz mixed with 620 Hz
0.5 sec. ON, 0.5 sec. OFF,
Reorder Tone (ROT)
480 Hz mixed with 620 Hz
2.5 sec. ON, 0.25 sec. OFF
Howler Tone (HWT)
2,400 Hz interrupted by 16 Hz
Continuous
Service Set Tone (SST)
350 Hz mixed with 440 Hz
Continuous
Ring Back Tone (RBT)
440 Hz mixed with 480 Hz
1 sec. ON, 3 sec. OFF
Hold Tone (HDT)
480 Hz mixed with 620 Hz
0.25 sec. ON, 0.25 sec. OFF
0.25 sec. ON, 1.25 sec. OFF
Second Dial Tone
440 Hz mixed with 480 Hz
0.25 sec. ON, 0.25 sec. OFF
0.25 sec. ON, 1.25 sec. OFF
Call Waiting Ringback Tone
440 Hz mixed with 480 Hz
1 sec. ON, 1 sec. OFF
Message Waiting Indication Tone
350 Hz mixed with 440 Hz
0.125 sec. ON, 0.125 sec. OFF
Ringing Signal
Frequency:
20 Hz (Nominal)
Signal Voltage:
75 Vrms (Nominal)
Interruption:
(1) 2 sec. ON, 4 sec. OFF (external calls)
(2) 1 sec. ON, 2 sec. OFF (internal calls)
Distinctive ringing is available for trunk routes and
class of service options.
Benefits 