I've got a Panasonic KX-T336 PBX. Three extensions, all fed from the HLC in slot 3, are exhibiting phantom ringing. I have tried swapping out the HLC, but this didn't help. I have also swapped out the CPU (and re-loaded the setup data), the LCOT, and the TSW, but nothing seems to help. Could the DISA card be at fault? The backplane? Any other ideas?

Thanks from a newbie!

I haven't worked on a 336 in years.
It's unlikely that it's a card.
It's more likely that these extensions are in line with the 1st 3 digits of a called number when someone forgets to dial an access code to get an outside line.
The voice mail may be calling.
What type of phones are these?

The phones must be analog propretary, i.e. 7020, 7030 or 7050. Yes, we had a similar instance where ext. 202, 240 and 301 had to be changed to something else because people were forgetting to dial 9 first for local calls. These are all area codes in our immediate area.

You might want to check their voice mail box's pager notification feature. SO many times, people put threir own extension number in there and it causes them to receive a call to their extension every time a message is left.

i don't understand do you mean that
you have 10 digit dialing?

Thanks for the replies, and Ed, that is an excellent graduation picture! I had not thought of someone forgetting to dial "9", but in this case, I don't think this is the cause of the problem. The two extensions that are frequently experiencing this problem are 111 and 112. Extension 171 has also occasionally had problems. All three of the phones are served from the HLC in slot #3. Most of the telephones are toll restricted and no area codes begin with a "1", so forgetting to dial "9" doesn't seem to be a likely cause. Also, for a bit of background, this system serves office buildings and homes in a small compound. The problem is often occuring in the middle of the night when it is highly unlikely that anyone would actually be dialing. Although we do have KX-T7030 and KX-T123230 phones, the ones experiencing the problem are just plain analog non-proprietary telephones. Any other ideas?

I forgot to mention that our system does not have voice mail - only a DISA card which allows an incoming caller to directly dial an extension.

do you have smdr setup on the system?

I've seen similar problems on multiple shelf systems. Do you have more than one shelf??

I think 96 station ports per shelf is the limit (288 per system. Are you close to that?

Did you use your terminal to "remove" the card and then reinstall it? (this would require rebuilding the extension numbers, etc)

Any available slots? Put the HLC in one of them and give it a whirl.

Check the "timed reminder" code for the system. Someone could be misdialing in the middle of the day and setting themselves up for a "reminder" call at a later time

Good Luck
-Joe
https://www.usedpanasonicphones.com

Thanks, KX-TDA, for the suggestion of setting up SMDR. This sounds promising.

Thanks also, Joe, for your suggestions of using the terminal to "remove" the card and then reinstall it, trying another slot, and checking the timed reminder code. I will try these suggestions and see what happens. By the way, ours is a single shelf.

I am Chief Engineer for KFBS - a large shortwave radio station - so telephone work is only a small part of my job. Even though this is an older system, it is new to us having been installed earlier this year. As such, I am really having to learn "on the fly." Thanks to everyone for your assistance!

I've had similar problems with the City of Tulsa phone lines. All of our lines are Plexar (Centrex), most are POTS, the rest are P-phones/ACD sets. ALL of our dial tone is handled by Bell, even though we have four digit dialing. The times that we have experienced "phantom ringing", we have found the trouble to be a bad cable/pair (either on Bell's side, or our side) causing static on the line. This static, at times, simulates pulse dialing the lower digits, i.e. 1, 2, or 3. So, with a line that has static (within our Plexar system - four digit dialing), it is very easy for it to dial extention numbers like x1213. That happens to be my extention number, and I have many voice mail's ("phantom ringing") that are nothing but static, from lines that are in trouble. Most of the time it will be after hours...2:00 a.m., or when it's raining. Anyways, my point is, you could have an extention within your system that is on a bad cable/pair. I say that because, you mentioned that it happens frequently on x111 and x112.

Just something to look into....hope it helps.

Later,
Rick

Thanks for the additional thoughts, Rick. Since the lines run underground, and this is a very harsh tropical environment (salt-spray, rust, corrosion, termites), this could very well be the problem.

And Joe, I forgot to answer your question about station ports. We are currently at 64.

Thanks! I'll keep you posted on developments.

i had this problem on a ta-624 and it ended up being a grounding issue, removed the ground and problems went away put ground back on problems back, changed the ground to a different ground and everything has been ok.

Work?

OK, time for an update. I am trying one thing at a time so that I will know what actually solves the problem. I have changed out the backplane, but this did not help. So, today I:

1. Re-loaded a much earlier set of backup data just in case the present data got corrupted, and then updated it with the recent changes.
2. Using the terminal, I "uninstalled" and then "reinstalled" the HLC card in slot #3 which feeds the offending extensions.
3. Checked the "timed reminder" codes. It seems unlikely that this is the problem since a three digit combination <*51> or <7*1) would be required. It seems unlikely that folks at three different extensions would make the same error in dialing.

I plan to see if the above changes help. If not, I next want to:

1. Remove the DISA card for a while to see if the problem goes away. I don't presently have a spare.
2. Try the HLC in a different slot.
3. Try different grounding.
4. Check the underground cable.

I also want to set up SMDR, but I don't have a serial printer. Does Panasonic make a serial to parallel interface?

Thanks again, everyone.

David

Panasonic doesn't actually make a serial-parallel interface, but there are plenty of other manufacturers out there that do. The last time we purchased them, we got them from a company called PI Manufacturing (909-598-3718) or www.pimfg.com.

OK, we may have a solution! It looks like Rick was on the right track when he suggested that a faulty cable could create noise thereby simulating pulse dialing.

Yesterday, I changed the extension number of the telephone most often experiencing the problem from 111 to 181. (This is only a 2 wire circuit feeding a standard telephone at one of the houses on the compound.) I then assigned extension 111 to the telephone on my desk. This is a Panasonic KX-T7030 telephone which will display the extension of the person placing the call. This morning, the problem did indeed occur on my telephone. It showed that the person calling was at extension 172. This is a vacant house. When I checked this line, I found that it is shorted and quite noisey. So, for now, I have disconnected this line from the PBX. I think this will probably solve the problem.

So, I would like to say thank you to everyone for your ideas. I greatly appreciate your assistance!

David Creel

P.S. Thanks for the link, Ed. I bought a "new in the box" serial to parallel interface on eBay. Once it arrives, I plan to connect a printer and use the SMDR feature. This should make future troubleshooting much easier! Thanks for the idea, KX-TDA.