sundance-communications.com/forum Forums Other TDM Phone Systems 1A2 and Comkey Telephones & Systems Access Intercom on WE 2565 without Selecting Line

Many years ago installers would add a 5th CO line to a 6 button set by replacing the last pickup button, normally the intercom, with the new, 5th CO line. When you lifted the handset AND did not depress any PU key, you got the intercom line. I haven't found this referenced in any BSP. Any help on how I would modify a 2565HK set for this? I need the T&R and A Lead for the intercom. Thanks!

There were some sets, notably the Stromberg-Calson 1800(?) series (5 line call director style) that offered this feature. I don't think it could be added to any set that didn't come with it.

Sam

B.S.P.502-525-901NY(C38.905). GS-S-69237 modification of 565 G, H and L sets that allowed the use of the exclusion key to pick up the intercom line when all five( or six) buttons on the set were used for C.O. Lines. A 17B ktu was controlled by the exclusion key. When the exclusion key was operated, the 17B disconnected the talking circuit to the line keys,and connected the talking circuit to the intercom. Contacts on the 17B also disconnected the a lead in the set so that if a button was depressed it would not give a false indication.

Correction- Only two sets of contacts on the 17B- The a lead was opened by the exclusion key contacts.

Thanks for the info; I do remember now that you had to pull up on that white exclusion key for the intercom!

The technical name for the feature was "switchhook intercom" and it was a nightmare when it was done with the 17B KTU. If the contacts on the exclusion switch were out of adjustment, the in-use line would go on false HOLD. It required pairs going back & forth between the set and the KSU, and if there were bridged sets on the same 25-pair cable, you were SOL.

Later, they took an Autovon set that had a 2-wire/4-wire "MB" type relay inside and modified it to create a SWHK ICM that required only one extra half-pair for -24Vdc to operate the relay. All the switching was done right in the set. The relay power was sent in on the Brown/Yellow lead.

The set was originally the 3568, and they adapted 256x sets to the new model number 2568HAA, affectionately called the "Ha Ha" set. The red HOLD button became the ICM busy lamp. Kool!

All this was made moot when the 830/2830 series of 9-line sets were introduced. Lots of buttons, and all on 25 pairs! Such a deal!

No kidding. Switch hook intercom service was a frigging nightmare. While I appreciate the creativity that was used to devise this strategy, not to mention the craftsmanship required to make it happen, it was a maintenance/service disaster.

It was NOT a disaster on the S-C sets. It actually worked quite well and without any problems. And yes, on the S-Cs the red hold button lit up on ICM. ( it was called "buttons-up-ICM" or something equally silly, but it did work.) I do remember the ha-ha sets, but more for the exclusion key and the disconnection feature.

Sam