NO JOY No inbound calls ring extension but the call can be heard

[jtpiano]

I have been trying to break down this problem to troubleshoot it with no luck. My system is configured as-
PBXinaFlash>ATA> where line (#1) feeds 4 phone jacks & line (#2) empty>phone plugged into one of 4 jacks

I can call outbound with no problem. with the phone plugged into the wall jack. If I have an inbound call I can answer the call (IF I happen to see the phone light up initially) however there is no ringing(while plugged into the wall jack). But, if I plug my phone directly into the ATA the phone will ring on an inbound call. Where do I start to troubleshoot?

 

[jtpiano]

Maybe I posted in haste. As I thought about my problem more it would seem to be an ATA issue. Can someone confirm? Sorry if I have posted in the wrong spot.

 

[briankelly63]

If it rings 1 or 2 or 3 phones and not 4 (or some combination) then you've exceeded the ATA's ability to ring four ringers. See: Ringer Equivalence.

You may be able to adjust the ringing voltage or frequency on the ATA to overcome this but maybe not.

 

[jtpiano]

It doesn't ring any of the lines. *What I was trying to convey above is that I have 4 jacks driven off the ATA. Not that I acutally have a phone in each jack. I only have 1 jack in use. All others are empty.) This is a new ATA so I must have missed a setting when doing setup. My old ATA gave up the ghost after 5 years. I did play around with ring voltage and sinusoid/trapezoid waveforms but no joy yet. I can see that when a call comes in the ATA does get the call.

 

[briankelly63]

What ATA is it? Someone may chime in who is familiar with it.

 

[jtpiano]

Cisco SPA112. I'm going to call Cisco on Monday as I do have support with it because it's a new device. (I just got it Friday, this last week) I greatly appreciate the assistance just the same! When I initially started this thread I wasn't quite sure where to isolate the problem down to. I don't understand why I can ring the phone if connected directly to the ATA but not if the ATA is connected to the 4 jacks in the house. I haven't made any changes in the house wiring and the phones rang when connected to my old ATA. (This also seems to point to a bad setting in my new ATA) I also double checked the wiring on the jacks just to be sure and reviewed some of the Cisco KB articles about the phone not ringing.

 

[briankelly63]

Ok I think I understand you now.... Back to basics.. The jacks are most likely all connected by the same cable that loops through your location. Some ATA's may be sensitive to being connected to a long loop vs. a phone. The specs on your ATA's phone port are listed below. A long cable run can introduce capacitance that can effectively surpass the REN range but I'm wondering if there may be a cable fault in your wiring. I would check the pair you are using with an ohmmeter. I would check the pair with nothing connected, one end shorted and from each wire of the pair to ground. The results should be as follows: infinite (no reading), some low value, infinite, infinite. I would also check the ring voltage setting. You could also try breaking the loop along the way and see if things start working. Also, you didn't mention how you have connected the ATA to the cable loop so CHECK THAT CABLE. I think you have introduced resistance along the way that doesn't effect talking but does effect the ringing. The line seizure spec shows it can tolerate a loop of just less then 1000 ohms but the ringer certainly won't work with that much resistance.

Ring voltage: 40-90 Vpk configurable​

Ring frequency: 20-25 Hz​

Ring waveform: trapezoidal​

Maximum ringer load: 5 ringer equivalence numbers (RENs)​

On-hook voltage (tip and ring): -46 to -56V​

Off-hook current: 18-25 mA​

Terminating impedance: 600 ohm resistive or 270 ohm + 750 ohm​

150 nF complex impedance​

Frequency response: 300-3400 Hz​

Return loss (600 ohm, 300-3400 Hz): up to 20 dB​

Insertion loss (1 Vrms at 1 kHz): 3-4 dB​

Total harmonic distortion (THD) (350 mV peak at 300 Hz): up to 3%​

Idle channel noise: 72 dB (typical)​

Longitudinal balance: 55 dB (typical)​

Off-hook threshold (line seizure): Rdc < 1000 ohm​

On-hook threshold (line release): Rdc >10000 ohm​

Rdc DC supervisory range: Rdc > 450 ohm​

 

[jtpiano]

I found my issue. All my jacks are home runs. (not in series) Once I removed the offending jack from the bus the phone rang. It's funny that the old ATA could ring the phone but the new one not.

BTW, you are right on the mark. Finding the fix really came down to understanding the electronics theory behind all this and taking some measurements with my meter. Now I just need to trace down the specific jack and see if a wire got pinched. (There was some remodeling done at my house a few months ago.) I'm going on the theory that the old ATA could handle the additional impedance present but burned out as a result of the long term effects of the extra stress on the unit. The new ATA wasn't nearly as tolerant. Differences in circuit design and tolerances between the two units could easily account for the symptoms I had here. I was able to verify that my settings in both units were the same for waveform type, ringer voltage, etc.

Many many thanks for your help!!! I just needed that little push to let me know I was going in the right direction. I was doubting my own troubleshooting at first and felt a little bewildered.

Problem solved

 

[briankelly63]

So that one cable run probably has a high impedance short that isn't low enough to pull dial tone but enough to prevent ringing. When dealing with copper the short may be between two oxidized wires, a screw, moisture etc. Add the cable run and you could easily be above that 10K ohm release figure.