Help with hardware issue?


I am trying to install a VoIP system in a small-ish farm community in South Africa. The only problem I have is the internet connection. I decided that we should get a sattelite connection, as bandwidth in SA is extremely expensive, and we can only get a 128k isdn line to the community(ADSL not supported there)

Now my question is : will this system work on the asterisk digium hardware? In particular the TE210P? I downloaded a pricelist from a SA supplier, but they listed it under ISDN for some reason?
Will this modem/router(what do you call it?) work with the hardware?

why would you need an internet connection for VOIP? if you have standard analog phone lines or can have a local telco terminate a partial T1 (depends on cost and how many lines you need) then why not get a card and plug into that, and use VOIP for the “local” calling network??? it would be MUCH cheaper than satellite, i would think, and would offer you the same exact features and would sound a hell of a lot better - satellite has too much latency, and you’d end up not being able to talk to anyone half the time…it just doesn’t work.

i think you need to do a bit more research as well, as it seems you’re confusing a T1 interface card (TE210P) with a network interface card…

how many concurrent outgoing/incoming lines will you need, and how many users will this be serving - tell us that, and we can tell you what you need.

Yeah, I am a bit confused here.

Basically, we will be serving about 200 households, and about 20 businesses. Roughly 250 phones. Most of the users only phone people inside the town, thus this can be handled on the local network.

My problem is with unique numbers for each. Line rental in SA is extremely expensive, we want to cut back on their(users) costs. We can probably make use of extensions, but it would be better if we made use of unique numbers. Do you need an internet connection to make use of DID?

What hardware do I need for this VoIP system to work properly?

First, lets say you set up the whole thing for your town, ie everybody can call everybody else in town over * using extensions or something.

Now the problem is you need DID service and some form of termination to the outside world. This can be done in one of two ways.

First, you can go the VoIP route. Get a Net connection of some kind, and find an ITSP (voip provider) who can sell you minutes and/or DIDs. Provision * accordingly and you are done.

The other option is the telco route. Find a/the local telco who can sell you a partial or full PRI (T1/E1) line with DID service. Each PRI line can support up to around 23 (or 31 for E1) channels, you may buy a line that has some or all of these channels configured (when you do not all of them its called a partial or fractional T1). The telco will also sell you DIDs (numbers). You can (and probably will) have more DIDs than you have PRI channels. This is fine, and it is because of the way a PRI works-
when you have an analog (POTS) channel, and a call comes in, the channel just rings (and a caller id burst is sent if you have callerid). You know the call is for YOU because YOUR line is ringing.
When a call comes in over a PRI, there are 23 possible channels it can come in on (and the call may not be for you). So (if set up correctly), the call will come in along with not only the caller ID (which is sent digitally over the control channel) but also what number was called- so you know who the call is going TO. Same thing when a call goes out- you can usually set your own CallerID (at least within the realm of DIDs you have) Thus, your PRI is used as a ‘trunk’ between the * box and your telco, allowing you to serve many more customers than you have lines.
edit: The number of channels comes into play here because that is the maximum number of calls you can have going at any one time. It can serve one customer/DID or 1500, but all together that line can only serve 23 CALLS at a time.

Hope that makes sense!

ironhelix couldn’t have said it better…

the big question for you is which is cheaper - broadband internet access or a full T1??? if your only internet option is satellite, i’d say that a T1 would be the way to go, or at least a partial T1, or even several analog lines. it all depends on what your concurrent external capacity needs to be. if you have 50 calls active at any time but only 4 of them would be going outside of your network, you probably don’t need a full T1. however, if you have 50 active calls and 20 of them are going\ outside of your network, you’d need a full T1, possibly more.