Author Topic: Miniature 10-line telephone exchange using 22 relays  (Read 20795 times)

Offline dylanc4

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Re: Miniature 10-line telephone exchange using 22 relays
« Reply #60 on: October 21, 2018, 11:27:17 PM »
Has anyone made this? If so can they post a video to YouTube and link it here?

I am thinking of putting this together..
-Dylan Cruz

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Offline rherber1

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Re: Miniature 10-line telephone exchange using 22 relays
« Reply #61 on: November 22, 2018, 09:58:46 AM »
I can now report that the 10 line exchange is now working...tests so far have shown no operational issues.

The final circuit now uses 32 relays mainly due to dispensing with the BCD calling line identifier and substituting it with individual calling line relays with lockout function. The ring cadence generator is now a double multivibrator which produces the standard UK/AUS 0.4 on- 0.2 off - 0.4 on - 2.0 off pattern. The original dial tone and ring tone feed arrangement is totally useless and has been replaced with a transformer feed arrangement. My 48V DC power supply also incorporates a 25Hz @ 80V ringing supply so the DT and RT are at this frequency.

My final arrangement consists of 4 boards all using wire-wrap technique. Board 1 holds the 10 line relays and the 8 relays in the dial pulse counter. Board 2 holds the A and D relays plus all other control relays. Board 3 is the ring cadence generator. The 4th board simply holds the tone feed transformer because there was no room available on the control board - where it would normally have been located.

When I get all the circuits tidied up I will post again.

Offline Owain

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Re: Miniature 10-line telephone exchange using 22 relays
« Reply #62 on: November 22, 2018, 10:49:10 AM »
Wow.

Offline dylanc4

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Re: Miniature 10-line telephone exchange using 22 relays
« Reply #63 on: November 26, 2018, 04:37:09 PM »
Cool!

I would LOVE to see a video on that if possible!
-Dylan Cruz

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Offline HarrySmith

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Re: Miniature 10-line telephone exchange using 22 relays
« Reply #64 on: November 26, 2018, 04:41:49 PM »
Sounds Great! When it is all ready would you post some pictures? I for one, would like to see it. I am sure others would be interested too.
Harry Smith
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TCI

"There is no try,
there is only
do or do not"