Don McKenzie wrote:
>
> Cassie Carstens wrote:
> >
> > Does anybody have some specs or pointers to Telephone Pulse Dialing
> > protoc. Pulse timing, interdigit times and so on.
>
> Mark is 33.3ms, space is 66.6 ms
> You will find it fairly international.

I concur. I recall it was originally 50/50 m/s ratio,
but relays took longer to open than close, hence the
change in ratios.

I have a paper app note demonstrating the 8052 BASIC
chip by driving a relay to produce pulse dialling.