B&K 4070A - Manual (Page 40)

BK Precision 4070A User Manual Rev.2.2
35
Ext Gating Input
This TTL compatible input can be used to gate the output signal on or off. Logic high voltage turns off the output.
For further information on the Ext Gating Input, refer to section 2.0.
Dualtone Examples
The following table lists the parameters for some common Dualtone.
Name
Frequency 1 Frequency 2 On Time (Ton) Off Time (Toff)
Dial Tone
350 Hz 440 Hz 1 mS 0 mS
Ring back 440 Hz 480 Hz 2,000 mS 4,000 mS
Busy 480 Hz 620 Hz 500 mS 500 mS
Reorder 480 Hz 620 Hz 250 mS 250 mS
DSN Preempt 440 Hz 620 Hz 1 mS 0 mS
European 420 Hz 440 Hz various various
Note: The Phase Offset field value may be set to any value to properly generate these tones.