I've read the discussion on the 110 'relay issue', but I'm still unclear if the 110 will reliably auto-default PTSN with a power/internet/voip provider failure.
Mark.P,
Last I heard, the hardware relay switch is gone. However an OBi110 work around for this is to use a Trunk Group which includes the Li in the list. Trunk groups cycle through the available trunks (sip/pstn) until it finds an available trunk to make the call. If the internet is down, it should go out the line. The problem with that is if the power goes down this strategy will fail. The only way to be certain is to have a second phone connected directly to the co line, since the pstn supplies it own power.
As QBZappy said, a using a trunk group could fix part of this problem. However, you would need to test to see if the "switchover" would be instantaneous. I have tried removing the ethernet cable and dialing [no trunk group] and it takes 50 seconds for the 110 to come back with a message so I don't know how it would work with a trunk group. Also, if your VOIP provider requires registration the trunk group idea probably won't take care of that.
As far as the relay goes, it can easily be replicated if you have some electronic expertise. Use a small 12v or 24v DPDT relay and any small "Ice cube" power supply similar to the one shipped with the Obi.
Probably not the simple answer you were looking for, but a couple ideas.
Thank-you both, QBZappy and ProfTech.
My plan was to install the 110 inline with the RJ31X jack(security system)--telephone company interface. Dial-plan all local calls for pstn and LD calls on paid voip service.
While I have 3-Obi202 units in use, and I am not afraid of a little experimenting, this 110 configuration needs to function without fail or at least fail in a working state. I am surprised that the 110 is not engineered to fail safe to the pstn line.
It appears as though my plan to install the 110, for simple, low cost, trouble free service in both my parents winter(FL) and year round homes, is likely un-workable.
Quote from: Mark.P on October 31, 2012, 03:57:05 PM
Thank-you both, QBZappy and ProfTech.
My plan was to install the 110 inline with the RJ31X jack(security system)--telephone company interface. Dial-plan all local calls for pstn and LD calls on paid voip service.
While I have 3-Obi202 units in use, and I am not afraid of a little experimenting, this 110 configuration needs to function without fail or at least fail in a working state. I am surprised that the 110 is not engineered to fail safe to the pstn line.
It appears as though my plan to install the 110, for simple, low cost, trouble free service in both my parents winter(FL) and year round homes, is likely un-workable.
Last paragraph summarizes it. Won't be trouble free. Will require someone with knowledge at times.
I hesitated posting this before, because the first comment was bound to be, "Yeah, but Obihai should have just left in the relay" and so on. I agree, but here is a fairly simple solution using a relay and a wall wart for those who don't mind hacking a solution.
This relay has screw terminals and an LED. It also works on AC or DC of various voltages so it should be easy to get a wall power supply to help. Then a couple of RJ11 jacks and a case. Not cheap but pretty easy to hook up. http://www.azatrax.com/track-power-relay.html
Without testing, looks like you would extend the phone line to also connect to 1NC and 2NC. The phone goes to 1C and 2C and the output (phone port) of the OBI goes to 1NO and 2NO. With no power, the phone connects to the NC terminals and the phone line. When power is applied, the phone connects to the output of the OBI.
The relay would be powered from the house power for automatic use, or with a battery or two and a manual switch for manual use. Of course, if you want to manually trigger the device, you could replace the relay with just a DPDT switch at a cheaper price.
My Obi is old enough that it has the relay, however the idea of using a simple DPDT switch had not occurred to me. Great, simple idea! Could even be located remotely from the Obi if you wanted or needed to.
The use of a splitter and an RJ-11 A/B switch like this one should do the trick:
http://www.amazon.com/Premium-RJ11-12-2-way-switch/dp/B000BSHG0S/ref=sr_1_1?ie=UTF8&qid=1351854794&sr=8-1&keywords=rj11+switch
Great idea MurrayB. I actually have one of those in the closet from years ago. In my case, I have the relay in the unit and no phone line for my 110 anyway.