atcomsystems.ca/forum Forums Other TDM Phone Systems 1A2 and Comkey Telephones & Systems 1a2 system

I bought those from Graybar Telecom in Dallas. I don't recall how much they were but they weren't expensive. If you don't find any let me know. I have have seen at least one upstairs and there should be at least one more up there as well.

As for the DTMF decoder, you can make an interface out of a non-polorized capicator and a 1:1 audio transformer across the audio pair that will monitor the line and feed the DTMF into your DTMF activated switch. Pretty basic to interface once you have the access device.

Shhhh. Don't wake Bill from his nap

Thank you Mr. MacGyver! I will call them first thing in the morning!!!

I'm impressed - you must have one helluva memory. Crap, I can't remember what I had for breakfast, let alone WHERE I BOUGHT something a few YEARS ago - LOL.

As for the interface, that's sounds fairly straightforward. I don't physiclly have the unit with me (I am presently on a contract in Lansing, MI. - and Gawd, do I miss TEXAS!, "Home Sweet Hole-In-The-Ground"), but I think I have a Melco intercom in the KSU, and was thinking that if I could get a handset out to the front gate (900 feet), I could have visitors to the base pick up the phone and ring the intercom line, then I could enter a DTMF sequence from the set I am using to talk to them, having the Melco decode it and trip a relay to open the gate for them.

Hmmmmmm......pondering, pondering, pondering, Zzzzzzz, Zzzzzz, Zzzzzzz.

Thanks for your advice and assistance (adding names to my Christmas Card list).

OK naps over. I can tell you're ashamed your lucky I don't have feelings. All 1a2 stuff I did was pretty straight forward, no gates, doors or any of that stuff. Could just do a ring down type circuit too, don't remember which KTU is used for ring down thought. I'll bet SOMEBODY does.

The interface is a breeze. I build them in a 3 line bisquit jack. That way I have 6 screw down points and have an RJ on one end. They work very well and give good audio quality. It should talk to your device with no problems. The other great thing about building the unit this way is that you get NO differential ground problems.

Kind of like Bill, I've never ran the DTMF over a 1a2 for a gate opener (since this was all way past my time) but hey, it's all basic electronics and relays, right Bill :toast:

Yes sir, I'd just take the locking screw out of the last button and use the A leads to open it, heck with sending DTMF to a box, just something else to go wrong. See what a nice refreshing nap can do for ya. :banana:

578th:

I have about 50 Melco S64-1 A-lead detectors on the shelf from years of supporting government accounts. They are new (old stock) in box. I will gladly give you one if you pay for shipping.

These things have a T/R input (from the CO) and a T/R output (to the fax). When the fax is in use, it provides an A/A1 contact closure to light up the line button.

Like I said, it's yours for the taking. Just toss me a shipping address. :toast:

We should have known Ev would be the 1a2 man to have the final answer

AWESOME!!!!

I just got off the phone with Graybar. They found 20 of them in Tampa ($22 ea.). I ordered 8. For those that may have interest, the Graybar part # is 88272846. I ma JAZZZZED! I didn't think I would ever find them. Thank you so much.

Ev, I appreciate your generous offer. That was really nice of you. I'm not familiar with the Melco units, and I'm sure they are quality. But I really wanted opto-isolated because of the problems I've had in the past with lightening strikes. And this TA-1 is the only one I've ever seen that was built on this technology.

YIPEEEE!!!

Now, I have 2 more questions this morning for you guru's.......

1.) I want to put fuses/circuit breakers on the T/R wires coming in on each line (one fuse/breaker on each wire). What amp fuse would you suggest? Slow or fast blow? Again, trying to protect myself (line cards) from lightening. I know this won't stop a direct or very close hit, but it is better than nothing.

2.) My 1A2 is presently set up for 8 sets (and intercom for all 8). What is the physical limitation on the number of sets I can hook up to the ITT 1A2? I'm sorry, but I am not a telco guy, so please forgive me if this is a stupid question. Something tells me the magic number is 16?

I can't tell y'all how much I appreciate your advice. It's great that I have found a bunch of guys willing to share their expertise on this subject.

(smiles)

Back to Graybar and get a Porta systems line protector, if you're not going to use any ringing current get the low rated, 30volt (I think). These things are quick clamp and will protect your telephone equipment. As far as numbers of phones on a 1a, don't know as I've every heard of a limit. Biggest I ever worked on had around 60 phones and everything worked fine. Now that's been awhile back (no comments), so can't remember if they had a beefed up power supply or not, I doubt it.

Like Bill said, Porta Systems. They have a 66 block that instead of bridge clips to bridge the center conductors it uses a protection device. If one blows, just remove it and plug another one in. I use them on most everything.