ITT 2500 Delay when clicking hookswitch

[rtp129495]

I know its not a rotary, but it is annoying. There is a delay in the phone when the hookswitch is quickly pushed. Its a 4-5 second delay. The the dialtone returns. Annoying because if your on a call and you accidently hit it lightly. The call is lost because the delay makes it think you meant to hangup. Does anyone here know how to bypass this problem/feature and make it work like a WE500 without the hookswitch delay? I am new to ITT stuff. and the wiring is slightly different.

[Adam]

A normal 2500 set should not do this, even one made by ITT.

Perhaps the set has a special feature designed to prevent switch hook flash.  I can see that a set with a special flash button might also be designed not to be able to flash via the switch hook.

Can you tell us the full number printed on the bottom of the set?  It will be something like:

250044(FBA)30M 788

Also, if we could see pictures of the inside of the set, we might be able to tell if you have some kind of special hardware inside the phone that is causing it not to function like a normal 2500.

[Phonesrfun]

I agree with Adam, in that until we see some specifics, all we can do is guess and surmise.

I do know that there are many phones out there that have been made in recent years that look like a 2500 on the outside, but contain electronics that allow for features not before present in the older models.

But, in order to really know, we need the kind of information Adam mentioned.

[Phonesrfun]

PS Regarding asking a touch tone question:

While the title of this forum is Classic Rotary Phone forum, and while the discussions generally follow along rotary lines, no appologies are needed for talking about:

• Magneto crank phones
• Manual phones, including candlesticks
• Touch tone phones
• VoIP and other modes (gasp!**)  

**Yes, even VoIP comes up becuause first of all, so many "Land Lines" are being provided by non traditional means these days, and our rotary dial phones don't always work on them the way we would like.

There is also the phone collectors C*Net that goes out over the Internet and allows collectors to not only connect their legacy phones to the internet and call each other, but some collectors have very elaborate electro-mechanical central offices connected this way, which really goes a long way to keeping the hobby alive.

[Adam]

While we're on the subject, I'm part of the C*NET, it's very cool.  To learn more, visit http://www.ckts.info or send me a message.

-Adam Forrest
Los Angeles Telephone, a proud part of the global C*NET system
C*NET 1-383-4820

[GG]

What that is:

The phone almost certainly has a button labeled Flash or TAP or with a little lightning bolt or some other designation along those lines.  That button generates a 500 millisecond (1/2 second) break in DC continuity to activate CO and PBX features such as three-way calling.

On ITT/Cortelco's and Stromberg-Carlson's version of that, the hookswitch is also timed.  But it's actually 1.5 seconds (1500 milliseconds) as needed to give a positive disconnect on CO lines or PBX extensions that use the Flash signal to invoke various features.

On a phone of that type that is working correctly, that delay is not 8 seconds, it's 1.5 seconds, and if you're getting 8 seconds of open-circuit (measure it), something's broken somewhere.

What to do about it:

The aspect of this that's bugging you is that the hookswitch is twitchy: just a slight touch and it opens the switch contacts and initiates the timed-break or timed-disconnect feature of the phone.  Fortunately there is a simple fix for this.

Open up the phone, look at the hookswitch mechanism carefully, and press it down a few times to see how it operates mechanically.  You'll notice that the two "prongs" or "ears" that are below the buttons in the cradle, are part of a piece of metal can travel between two "stop" positions in the stationary part of the cradle mechanism.

You can gently bend these "ears" down slightly, relative to the rest of the metal piece they are part of that moves the switch contacts.  Do this just a little at a time, and evenly for both the left and right one.  Do it a little and then put the housing back on the phone and notice that the hookswitch button does not stick up as far as it did before.  Fiddle with both the left and right "ear" until both hookswitch buttons have about 1/8 inch free play between their "normal off-hook" position, and the position they would take if you pulled them all the way up to the top of their possible range of travel. 

This will make the hookswitch a little less "twitchy" because it will allow a little more room before the switch is actuated and fires off the disconnect timer. 

There are other more or less sensitive adjustments you can make to a hookswitch to give it a little more "travel distance" before opening the switch contacts, but this is the most obvious one.

[rtp129495]

Heres the model #:

250044-MBA-27F 8-97   H

I have posted pics of it below as well. I hope this helps.

[Adam]

Yep, it's like GG said, and I surmised, you've got a set with a flash button.

If the circuit on the touch tone pad with the flash button is inhibiting flashing using the switch hook, that means the one or both of the switch hook contact pairs is probably connected directly to the touch tone pad, and not to connections on the network, the way they would be in a normal 2500 set.

To circumvent your switch hook problem, you need to remove the switch hook from the connections on the touch tone pad (and put a short in their place to make the connection they'd normally make) and then wire the switch hook to the network as a normal 2500 set would be.

The switch hook contact wire pairs are:

Slate Yellow and Slate together/Slate Brown
Slate White/Slate Greeen

Slate Red/Slate Black (these should be OK, they close across the receiver while the phone is on the hook and do not affect TIP and RING part of the circuit)

(Newest phones may not have slate/color pairings, may just be solid color, like Yellow, Brown, etc.)

I can give more details if you need more.

Does anybody have the practice for this set?  That would give us directly the info about the wiring changes we need to make (as opposed to making educated guesses).  The operative part of the ITT stock number which tells us this phone's special feature is a flash button is 27F.

[rtp129495]

OK here's some wiring info

Slate with green is hooked to yellow wire on line cord through the network.
Slate/red hooks to dial
Slate/black hooks to dial
Slate/white isn't hooked to anything and is taped up(like this when i got it).
Solid Slate is hooked to orange with red on network that goes to dial.
Slate with brown is hooked to dial.

The funny thing is when only slate/red is unhooked by itself does the hook-switch act like a normal 2500/500 hook-switch. Is this correct? I worry leaving it disconnected is bad?  if I disconnect slate brown the phone doesn't operate. disconnecting slate/black doesn't do anything and phone still works. This seems to be at odds with wiring it to network as you stated. Am I missing something? there are 3 wires from hook-switch to dial. the forth is not hooked up (slate/White).

[Adam]

Well... you're right, that's slightly at odds with what my older ITT diagrams say the color of the switch hook leads are.  If you remove the slate/red switch hook lead and it makes it work like you want, then removing the slate/black should do the same thing.

However, you can't damage the phone by having it improperly wired, either it works as you expect or it doesn't.

I'd say that if removing the slate/red switch hook wire undoes the switch hook flash prevention, and that:

a) You get dial tone
b) You can generate touch tones
c) The ringer rings
d) You can be heard (it transmits)
e) They can hear you (it receives)

then you solved your problem!  Good work!

Don't forget to tape and store the lead so that it can't touch something by mistake.  Don't cut off the lead as you may want to restore it to its original state someday.

[rtp129495]

it does all of those things i guess im good and i learned something! Thanks!!!

[Adam]

Coincidentally (I assume), Cortelco 2500 diagrams were just posted to the TCI forum. (http://tinyurl.com/kvwz86)

Attached below is the wiring diagram for the 2500-27F phone, which confirms the slate/red and slate/black switch hook leads are associated with the flash button.

[G-Man]

Coincidentally (I assume), Cortelco 2500 diagrams were just posted to the TCI forum. (http://tinyurl.com/kvwz86)

Attached below is the wiring diagram for the 2500-27F phone, which confirms the slate/red and slate/black switch hook leads are associated with the flash button.

Thanks for taking the time to scan this document.