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voip to landline ca-pability

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w8erd
voip to landline ca-pability
We have a need to call out from a voip phone on our mesh network to landline numbers.   
What is the easiest way to do that?

Thaks!

Bob  W8ERD
kj6ffp
You will need a PBX system
You will need a PBX system that has land line ports on it also know as FXO ports.  Or if your mesh system has a gateway then all you need is either a PBX with a SIP service/VOIP service or if only certain phones need to call outside numbers then all you need is phones that you can add a SIP account/VOIP service onto.  
KG6JEI
Very good answer.
Very good answer.

I do wish to elaborate with a little bits of pro/cons of both as I see them:

Depending on what you have SIP gateway as mentioned is the absolute easiest but it's very heavily dependent upon a high speed low latency path to the global internet.

Mesh nodes installed at corporate data centers may be able to easily get away with a SIP connection even in an emergency (depending on exact specs of the disaster) as most of those type facilities are "hardened" to run onsite generators and have multiple telco routes. But this very much will depend on your area, but sip is certainly one of the easiest most flexible methods to use. 

POTS line adapters are a mixed bag as well. Some areas POTS is served by microwave links, in other areas POTS is going away altogether. When it works it's more likely to be up then residential internet, but it also runs a risk of "circuit overloads" at the central office. That said this sort of setup can be the easiest to integrate into a mobile communications truck that shows up with a bank of phones, you simple say "hey hand me 4 line wires" and you can link into the brought in infrastructure (cell van, satellite uplink truck, and sometimes depending on the phone system, it could allow you to "plug in" to a served agency and be an internal line in the facility and eventually out to pots) (of course if the served agency already offers SIP for its internal phones having them provision a few lines for your mesh PBX isn't hard either)

in both cases make sure to evaluate your area, asses what the likely disaster scenario are and evaluate how those will impact the planned deployment 
w8erd
I don't understand. There is
I don't understand. There is no internet involved here, or POTS telephones.
We seek a simple box that will sit on our mesh network and enable POTS calls to be made from IP phones on the network.
I am also curious as to the details of how calls would be placed.  I assume the IP phone would place a call to the box.  But then how does it tell the box what
POTS number to call?   Or does the IP phone use some special syntax to communicate this as part of the initial call?
Sorry if I am naive about this,

Bob W8ERD
KG6JEI
"I don't understand. There is
"I don't understand. There is no internet involved here, or POTS telephones.
We seek a simple box that will sit on our mesh network and enable POTS calls to be made from IP phones on the network."

First keep in mind the POTS Network is basically anything that interfaces with the telco systems, even SIP trunks are considered a part of the POTS network as they have a Dial In Direct (DID)(a phone number) assigned to them.

That is why we mentioned theres at least two ways to link into the POTS system, one is to use SIP TRUNK (which is internet based) to get yourself on the POTS network.

The other is using what is known as an FXO gateway which is a "line receiver" that takes a telphone line received from the telco (or other source like an office PBX) and converts it from analog on copper  to  digital over the IP network.

How you tell the device to call the POTS number will depend on what you buy hardware wise. If you hook it into an Asterisk PBX you just configure your dial plan and can do the classic "9 to get out" or could program it  "anything that looks like a phone number dial it direct" or however else you want it.  This would be especially the case that its dependent on your phone server if its a "Line Card" and not an external device separate from the mesh phone system.

If you buy just a  "SIP to FXO" adapter they would probably accept POTSNUMBER@ipaddress as how to dial them from your mesh phone (or from your PBX)  much how SIP trunks work.

Both the "SIP TO FXO" or a "Line Card" in the 2 paragraphs behave as "telephone" or otherwise stated "consume dialtone" to provide POTS connections (copper) to the IP network.

(the opposite is an FXS adapter which provides dialtone like a telco would)

If you want all this prebuilt for you perhaps this thread is relevant: http://www.aredn.org/content/shelf-pbx-appliance otherwise its a matter of "seek out hardware" to meet what your implementation desires are.
 
w8erd
POTS to IP phone link
Thanks for the advice.  After looking around, the Grandstream HT503 would appear to perform this function.
Does that seem reasonable?

Bob

 
K5DLQ
K5DLQ's picture
this is a VOIP to analog
this is a VOIP to analog phone adapter and will let you use standard analog phones on your VOIP network.  It will not connect your VOIP to the public POTS phone system to call *ANY* analog phone number (ie. 1-800-555-5555)
KG6JEI
Darryl,
Darryl,

I haven't  read the full manual but http://www.grandstream.com/sites/default/files/Resources/ht503_wp_hop_on... to imply it will do VOIP to PSTN with a PIN code.

You see something I haven't? I'll admit my first thought when I saw FXO+FXS is "ok is that just a passive relay or a real FXO" but guide seems to imply it's a real FXO.
 
K5DLQ
K5DLQ's picture
oh.  Maybe so.  I just don't
oh.  Maybe so.  I just don't recall read FXO being at that price point.  I may be wrong there.
 
w8erd
Grandstream HT503 works as VoIP to PSTN gateway
I have investigated this at some length, and had many discussions with the Grandstream support engineer. The HT503 works fine to call from an IP phone on the mesh to any arbitrary PSTN number.   However to call in the opposite direction, from PSTN to VoIP, it works only to a single specified IP phone.  The manuals
are long and complicated, and wrong in this case.  A big stumbling block is they do not tell you that when calling the HT503 IP address to make a call, you must specify port 5062.  The HT503 costs about $50 on Amazon, and $25 on Ebay.  This would seem to be a very useful addition to many mesh systems.

Bob W8ERD
KE6UPI
Sounds like you need to


Sounds like you need to bridge your IP phones from your Mesh Network to the real world. Your telephone company gives you a Plan Old Telephone Service. (POTS). You'll need a gateway that has SIP and a FXO port.  Look for a used SPA400 (Linksys or Cicso) The SPA400 can also use a VoIP SIP account if you do get public Internet.



FXS gives a dial tone. FXO is what use to connect to the POTS

You then can route calls using 9 to dial out to the real world. 

David

P.S. Or Learn Asterisk PBX
 

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