No keyboard operation with FZGT or i-Telex


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JDAngus
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Registriert: Di 14. Nov 2017, 17:28
Hauptanschluß: 76470

Re: No keyboard operation with FZGT or i-Telex

#11

Beitrag: # 21138Beitrag JDAngus »

87 v, + on c - on a. Nothing connected to the i-Telex box.
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JKde
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Hauptanschluß: 234280 jochen d

Re: No keyboard operation with FZGT or i-Telex

#12

Beitrag: # 21140Beitrag JKde »

I assume the 2 cables from the i-Telex are inverted (switched polarity).
In idle mode c is - and w2/a is +.
On imcoming call c is + and w2/a is -.
The control unit reacts on polarity!

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Jochen (Würzburg)

234280 jochen d (T100 75Bd)
234281 jk200 d (FS200Z 200Bd)
234200 fablabwue d (Lo15, T37, T36Si, T68, T100S, Lo133) [nur zeitweise online, wenn FabLab geöffnet]
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FredSonnenrein
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Re: No keyboard operation with FZGT or i-Telex

#13

Beitrag: # 21141Beitrag FredSonnenrein »

Note regarding Jochen's drawing: The grey Box "Telex" should include the call control unit.
Grüße,
Fred Sonnenrein, Braunschweig
i-Telex 952741 (Lo133), 8579924 (T100s), 781272 (T100), 792911 (T68d) oder 531072 (T.typ.72)
Bei besetzt oder gestört bitte 531002 versuchen.

Topic author
JDAngus
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Registriert: Di 14. Nov 2017, 17:28
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Re: No keyboard operation with FZGT or i-Telex

#14

Beitrag: # 21162Beitrag JDAngus »

I'm almost embarrassed to admit to what the problem was.
At some point in time I added an RS-232 to loop converter across the Signal jack on the Call Control Unit.
It's supposed to be 100% passive with no serial connection.
At some point in time, the MOSFET opto-coupler across the keyboard line shorted.
Well that did a splendid job of not letting me type anything on the Lo-15b.
RS-232 adapter

The Call Control Unit is working correctly now.
Both Local and outside connections. I type, it prints.

Thank you to everyone that helped me chase my tail around in a circle. :whack:

Jeff
i-Telex 76470
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