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General Support => Installation and Set-Up (Devices) => Topic started by: n4mwd on December 01, 2017, 06:24:22 am

Title: Weak Ring Current on Obi302
Post by: n4mwd on December 01, 2017, 06:24:22 am
I have the Obi302 configured and working mostly like I want.  However, when an incoming call is received, I get one short ring burst, then after about 6 seconds, another short ring burst.  If I start unplugging phones, the ring is normal.

The 302 is replacing a grandstream 502 that had no problem with the number of phones I have.  The gs is rated for 3 REN and the obi is 5 REN.   So the obi should be better not worse.

So I'm thinking either this 302 is bad or there is a configuration issue.

Does anybody know if there is a setting somewhere to boost the ring current?

Title: Re: Weak Ring Current on Obi302
Post by: SteveInWA on December 01, 2017, 11:40:01 am
You can try increasing the ring voltage (not current) by going into OBiTALK's expert settings section, and try increasing it, say, 5V at a time.  The maximum voltage the module will produce is 82V.

See my screenshot attached.  More likely, one of your telephones is bad.  Are these ancient Western Electric 2500 or other similar phones with electro-mechanical bells, or more modern phones with electronic ringers?  The right way to troubleshoot this would be to unplug one phone at a time, and see if it cures the problem.  If not, plug that phone back in, and unplug another phone, retest, lather, rinse, repeat, until you find the dud.

Title: Re: Weak Ring Current on Obi302
Post by: n4mwd on December 05, 2017, 06:37:37 pm
Thanks for the reply.  I increased the ring voltage to 80.  It seemed to help a little, but one phone, which is the farthest away (~200ft) cannot seem to make it.  It was a bell 500, but I replaced it with a trimfone with an electronic ringer, but it still doesn't work.  No problems dialing out.  Maybe something to do with the length.  Several of the closer phones are the mechanical bells.

What I don't understand is why the old grandstream rings all the phones mechanical or not.  Never a complaint.  However, in all fairness, the grandstream failed on that same line by having excessive white noise for some stupid reason - which is why I bought the OBI.

Should I play with the current and see if that helps?

Title: Re: Weak Ring Current on Obi302
Post by: SteveInWA on December 05, 2017, 06:52:20 pm
Comparing the OBi device to a Grandstream device isn't relevant, since they use different electronics.

You are probably in the 0.001% of the user population who is trying to power a bunch of ancient electro-mechanical bells with an OBi.  You simply found the limit of how much power can be pumped through your home's telephone wires over a long distance, with multiple inductive loads on the wires.

There's nothing else you can do, other than to go back to using the Grandstream, or re-wire your house, or stop using so many antique phones.

Title: Re: Weak Ring Current on Obi302
Post by: azrobert on December 05, 2017, 08:33:51 pm
You could try connecting one or more phones to the Grandstream then route calls to/from the OBi302. Most homes are wired for 2 lines, so you could use the 2nd line to connect the phone(s) to the GS. You might need a 2 line splitter.

Title: Re: Weak Ring Current on Obi302
Post by: n4mwd on December 10, 2017, 07:34:23 am
I compare it to the grandstream because the REN specs on the OBI are better.  The 302 has a REN of 5 and the GS is only 3.  I do have several phones with mechanical bells.  The electronic tweeter bell phones are too hard to hear.

Just to be clear, the problem is not a weak ring, the problem is that they (all phones) start to ring and then stop, then repeat for the next ring.  That is, instead of ringing for 2 seconds per cycle, they ring for 1/10th second.  Sort of like the obi tried, but hit some sort of current overload or something.

Its not incorrect ring cycle programming because if I unplug enough phones, it works normally.

So I'm thinking now that if a REN 3 can ring all of the phones, a REN 5 should be able to ring that plus more.  Is that correct logic?  If so, then it may be that my obi is defective.

Title: Re: Weak Ring Current on Obi302
Post by: SteveInWA on December 10, 2017, 03:28:22 pm
You keep returning to your original argument, that the OBi should work because it has a higher REN.  The reality is, ancient mechanical bell phones that are perhaps 50-70 years old, have old, corroded, rotten internal "networks" (an inductor/capacitor) that may or may not still be functional.  Add to that, house wiring that may be altering the impedance of the line.  Yes, in theory, 5 REN is better than 3 REN.  However, your real-world test, in your house,
 with your phones
, fails.  There is no guarantee that every phone will ring as if in a laboratory test using fresh, new components.

I described, in my earlier post, a troubleshooting procedure to determine if one of those old phones is causing the problem or not, by systematically unplugging one phone at a time, and seeing if the ring behavior changes.  If one phone causes the problem, but not the others, when all but one phone are connected, then that phone is a dud.  You can power that one phone with the Grandstream and leave the rest on the OBi.

Title: Re: Weak Ring Current on Obi302
Post by: n4mwd on December 12, 2017, 04:37:07 pm
I did the test you suggested and the only anomaly is that the phone with the long run does fail with fewer phones connected when it is connected.  Before I started this thread I replaced the bell phone out there to a brand new electronic phone.  I was surprised that it made no difference. 

So it just appears that there are too many phones, electronic and bell combined, on one obi line.  I'm thinking that the only workaround is to split the phones around the two obi lines.

My guess is that the GS did not have current limiting circuitry to shut off the current if more phones were connected than allowed, and the obi does.

Title: Re: Weak Ring Current on Obi302
Post by: kb3pxr on December 27, 2017, 12:24:37 pm
Try the following settings:
Ring Voltage: 85
Tip/Ring Voltage: 52
Off Hook Current Max: 27*

* If you aren't using electronic phones, go ahead and crank this to the full 45.

This get's the ring voltage as close to Bell Spec as possible, loop current to a sensible range (Obi really should have the default as 23 as that's the minimum for a real line), and the Tip/Ring Voltage simulates the Central office floating the batteries (normal condition).

I'm not sure this will help as I'm not sure how Obi rates REN on the adapter. Grandstream (who you are comparing to) has a 3.0 REN limit assuming a 1km line. Since your line isn't a kilometer long, the Grandstream will actually let you run a bit higher. Currently I'm on a Grandstream device with Vonage (test page is available in user mode btw) and my 1.0 REN electronic phone reads somewhere between 0.3 and 0.4 REN to the ATA.