atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services Cabling Telephones Systems Wiring Reusing 1A2 25-Pair Cabling for an Avaya Partner

My dear 91yo Grandmother has a large house with a 1A2 system installed in 1967 (says Installed 1967 by HERB on the chassis!!). Up until fairly recently the system has given great service. Really, how many things nowadays last 40 years??

Now the system is starting to really have issues, so she is finally ready to upgrade to something more current. She had someone come out and take a look at the cost to replace the system. They see her big house and the price magically becomes $8,000 and they want to rewire the entire place.

Although not a telephone guy by trade I have experience with data/tel cabling and have installed 3 Panasonics and 3 Avaya Partner systems to date. I have decided to take it upon myself to install another system for free. I have purchased a suitable used Avaya Partner R6 system to replace the 1A2.

I'm making a huge assumption that the existing 25-pair RJ21/amphenol cable will be absolutely fine for the new system (reused). I intend to put RJ21 to RJ11 (amphenol to modular) adapters on the station end of the cabling, terminated on the other side to a 66 block where it will be fed into the Avaya KSU.

Am I on the right track? If anyone has done one of these types of conversions reusing existing 1A2 wire, I'd love to hear about it.

If you want to see some pictures of this dinosaur, let me know.

I searched around the forums and couldn't find a good answer to my question, so please be kind if this is a redundant post.

Well, your terminology is a little bit off, but there's nothing wrong with using 25 pair to modular adapters. That is why they were invented to begin with. Partner systems do not require anything special other than two pairs to operate. You will be fine.

259A (single) or 258A (multiple jack) adapters are perfect for your application. If you'd be comfortable using a patch panel at the equipment end, just maintain a 568B wiring pattern with these adapters and it will work. Don't worry about a thing.

Thanks for the reply and giving me some piece of mind! The people in here are really great..

Well, maybe. The problem I find with this type of conversion is that the 25 pair is often looped to many locations. The 1A2 phones are all bridged on the same pairs whereas modern systems like the Partner need separate pairs run from every phone back to the KSU.

Certainly 25 pair that is looped can be made to do that but don't expect to just plug a 259A into each Amphenol. You will have to cut the Amphenols off and use a regular jack wired to the correct two pairs of the 25 pair after you make the proper arrangements at the other end.

I doubt that there is any need to rewire, but whoever is going to do it needs to know what they are doing. It's not plug and play.

-Hal

What Hal said! The chances of those 25 pairs being home run individually to the KSU are 1 in .....1000? Normally 3-4 phones operate out of one 'can' centrally located in reference to the telephones it is supporting. Then 1 cable runs back to the main cabinet. All line buttons and signaling EXCEPT the IC buzzer, are commoned on all phones. Now, I'll bet you see the problem! Unless you 'study it out' and understand it for sure, you could get inserious trouble and leave 'Grandma' without service. Not good. If I were you, I'd punch the INSTALLER tab at the top of the page. John C. (Not Garand)

That still doesn't help with the "other end". Then you would have to plug the phone into the one and only one correct jack on that harmonica. It's way too easy to have more than one phone on an extension with those. When that happens Partner phones will do something, and that's usually confuse the hell out of someone who doesn't know what's going on.

I agree with John, get someone who knows what they are doing to get the wiring working for you.

-Hal

You can try putting system next to old 1A2 system,then going to existing 25pr. cable on upper floor and cut off cable head and use first 2 pair on new jack,cross connect to Partner system and test.Make sure all old phones and any other phone devices are unplugged first. Then go to next phone location and use pairs 3 and 4 do same and test.This will work as long as you never duplicate pairs and do not short out any of the cut wires from cables. Although this will work,You can never remove any of the old cables{cut} without shorting out the entire system.

That's pretty much what you have to do. Put extension 10 on the w/bl and w/or and wire a jack to those pairs where x10 is going to be. Do the same with x11 on the w/gn and w/br and so on. Only problem is that you won't be able to do any more than 12 extensions ASSUMING all 25 pairs are cut through on all blocks which they usually are not. Normally you can count on three pair per line on the old 1A2 but that's about it. Like I say this is going to take some work.

-Hal

From what I count, all 25 pair cables are home runs to the basement (every phone has a dedicated 25 pair) where the 1A2 lives currently, so I think I'm good in terms of the existing cable. The 'can' LightingHorse speaks of is actually located only 20 or so feet away from the 1A2.

Just to give you a scope of work here:
Lines: 3
Stations: 10

If the amphenol/modular adapters (not harmonicas per se, just a single RJ11 jack connecting to pins 1,2,26,27 - www.phonegeeks.com/modtoamad.html SE153-AM-01) do not work for certain stations/locations I plan just to cut the amphenol off and use a standard 2 pair jack. I've planned on at least a few being hacked to death or some pairs not being usable.

When I get home I'll post some pictures so you can see what I'm dealing with. You can then tell me if I'm crazy for attempting this alone.

Thanks to all who replied.

Mike