atcomsystems.ca/forum Forums TDM Business Telephone Systems Avaya - Lucent Telephones & Systems Partner ACS R6: Contact closure on Page port has resistance?

Hello,
This is my first post. Please pardon any faux-pas. About me: Although my real job is IT security, I "manage" as a volunteer the wiring and systems for phone, PA, computers and power in a summer camp in Maine. We have 24 buildings scattered on a 1 square mile property, with many 600-feet cable runs in trees and utility poles.

Currently I am using the Page port (inner pair) on our ACS R6 for feeding voice into a 70V amplifier.
I am also using the Contact Closure port and a Contact Closure Adjunct for a dry contact, this triggers relays in a home-made system which opens all zones in our network of 70V speakers. This works well but it is awkward and error-prone, as it requires 3 manual operations: activate contact (F41), page (I70), deactivate contact (F41).

I've read that the outer pair on the R6 Page port is supposed to be a dry contact, which would be great for our needs.
However I tested this by measuring the resistance on this pair (dirctly on the ACS port), and when activated the resistance does not drop to near zero as expected, instead it reads around 40 ohms. This fails to activate the relays in our installation.

Is this normal behavior or is my unit defective? Or maybe my understanding is wrong?
Thanks for any help you can provide.

If 40 ohms is too much resistance for your application, use it to drive a slave relay.

Workarounds are possible, yes.
But I'm wondering if this is normal. Maybe this is wrongly described as a dry contact, or maybe something's wrong with my unit.

I'll defer to Tommy on this one, I assume he's saying that 40 ohms is normal. I've never had reason to measure the contact resistance of the contacts on the page port. If somebody says otherwise I can do that.

-Hal

If someone ever has the opportunity to make this measurement on a system, I would appreciate the help.

That is, put an ohm-meter on the outer pair on the page port, then activate a page (I70), then measure the resistance, then hang up.

TIA

I know this thread is getting a little long in the tooth, but I just took a measurement of the dry contact's resistance on the page port of my ACS R6. It measured 22 ohms. It's obviously not a true "dry" contact, and more likely a solid state relay type of thing. Could be a small triac, or back to back SCR's, who knows. Polarity definitely did not matter, and the resistance was equal in either case. Tommy is spot on about using a slave relay. I definitely wouldn't try to pass more than a few hundred milliamps through there. I don't know off hand what a typical 12 or 24 volt relay draws, but that'd be about it.
Thinking about this for a moment, it could also have a PTC thermistor in series with the contacts as a way to limit current through it. I'll have to take some measurements at different ambient temps to see if the value changes. I know I'm totally going GEEK-O here, but I'm trying to be thorough. Interesting side note, I picked up an old merlin 410 with some dead ports on it. Turns out the only thing that had failed was the 48 volts coming out of the ports to power the set. The culprit? Failed PTC thermistors that limit the current on the 48 volt pair in case of shorts or other damage. A few bucks at the electronics store had all the ports alive and well again.

For some reason I failed to see your answer before today.
Thanks for trying this!
Now I know my system is "normal" and I'll look into this slave relay suggestion.