atcomsystems.ca/forum Forums Other TDM Phone Systems 1A2 and Comkey Telephones & Systems Chaining 66 blocks with AMP connectors

Old ways are the best!

Wow! Very Impressive!

Sam

One of the people who recently purchased my board made a demo video for his 4 phones here:


I did fix the problem he described about the line lamp flashing during CO rotary dialing, apparently no one caught this including myself until he noticed it.
Turned out to be a simple software tweak, so I sent him a new chip to fix his board; so problem should be solved.

Just found the answer to the question I asked earlier in this thread (comment #629330 - 04/23/19 06:53 PM) asking about the specs for rotary dialing.

I found a BSP document 975-110-100 "Customer Loop Signals and Signaling Systems" (Jan 1980) that mentions the spec for dialing:



In particular the specifics of rotary speed and make/break pulses, which says the rate of pulses is 10 per second, with a between 58% and 64% break ratio (how long to break vs. make). Basically, a slightly longer open time than closed during pulsing. So if you do the simple math, if a complete pulse (on+off) must happen in a 100ms (1/10th of a second), the contacts need to be open between 58ms and 64ms during that 100ms.

The timing of old uncalibrated dials might be off that spec by a bit, so if someone wants to read old equipment, one should be pretty forgiving.

In the end, the technique I ended up using was so forgiving you could very carelessly flash the switchhook by hand, and still accurately dial without problems, so I didn't really have to pay much heed to the spec. But it is good to know what the spec is and see it in a document that is appropriate to define it.

I know the inter-office signalling was much faster; I recall dialing long distance back in the 80's and you could hear the fast inter-office dial pulsing during the connection process, which I'm sure Evan Doorbell has a million recordings of..!

"A digit is dialed when the rotary dial is pulled off-normal (clockwise direction.)"

WRONG!

A digit is dialed when the previously-pulled dial IS RELEASED.

Dr. Semantico.

It goes on to day exactly that, releasing the dial opens and closed the contacts corresponding to the dialed digit. Unless you're going to to pull the dial and pause it there for all eternity, digits will be dialed as a function of pulling the wheel

Yes, I read the whole thing, too. And yes, the released finger wheel starts the dialing. It's just a case of the technical writer tying his shoes before he put on his socks.