NCU Parameters
D418 136 SM
Address Function Unit Remarks
68052C Busy tone ON time: range 2
68052D Busy tone OFF time: range 2
68052E Busy tone ON time: range 3
68052F Busy tone OFF time: range 3
680530 Busy tone ON time: range 4
680531 Busy tone OFF time: range 4
680532
Busy tone continuous tone detection
time
20 ms
Busy tone signal state time tolerance for all ranges, and number of cycles
required for detection (a setting of 4 cycles means that ON-OFF-ON or
OFF-ON-OFF must be detected twice).
Tolerance (±)
Bit 1 Bit 0
0 0 75%
0 1 50%
1 0 25%
1 1 12.5%
680533
Bits 2 and 3 must always be kept at 0.
Bits 7, 6, 5, 4 - number of cycles required for cadence detection
680534
International dial tone frequency
upper limit (high byte)
680535
International dial tone frequency
upper limit (low byte)
Hz (BCD)
If both addresses contain
FF(H), tone detection is
disabled.
680536
International dial tone frequency
lower limit (high byte)
Hz (BCD)
If both addresses contain
FF(H), tone detection is