Appendix B; Dial Pulses - Multitech MultiModem MT2834MR6 User Manual

Appendix

Appendix B

Dial Pulses

When you pulse dial, as when you make a call with a rotary dial telephone, your telephone or modem
generates codes in the form of pulses that simulate the opening and closing of old-fashioned electric relays,
or switches. The number of pulses in a code are the same as the digit they encode; thus, the digit 1 is
represented by one pulse, the digit 2 by two pulses, etc. In Figure B-1, the digit 2 is pulse dialed, followed by
the digit 1 . Each pulse consists of an A ms open (break) and a B ms closed (make), where A is either 60 or 67
ms, and B is either 40 or 33 ms, for a total of 100 ms per cycle, or a rate of 10 pulses per second. The
interdigital pause time is 800 ms. The pulse ratios are controlled by the &P command.
Figure B-1. Dial pulses
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