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Can PlusTalk replace ISDN?

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Can PlusTalk replace ISDN?

Right now, I'm paying about a grand a year for an ISDN2e service running four extensions via a small PBX. I have a 2Mbps business broadband service from PN hanging off an additional PSTN connection that is only used for ADSL. My router is a Netgear DG834GT and I have a D-Link DSL-G604T spare so that I can check whether the hardware or line is broken if a fault occurs.

ISDN means that I can have two calls simultaneously and any extension can pick up any incoming call. If I have more than one VOIP phone, is it possible to have more than one incoming call active at once (e.g. if I'm connected on one call, will my other VOIP phones ring for a second incoming call?) Similarly is more than one outgoing simultaneous call, or a combination of incoming and outgoing calls possible? IOW, can PlusTalk effectively replace my existing 2-channel system?

Also, is there a good guide that will tell me what kit I need, and how to set it up?

TIA,

Geoff
9 REPLIES
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Can PlusTalk replace ISDN?

I would be very wary of replacing POTS with VOIP entirely. If your internet connection goes down - and they do from time to time - you have no telephones! That includes the ability to dial 999.

Also Plustalk cannot ATM offer a geographic incoming number, which is not good for business. You could have a local Asterisk server that would integrate PSTN with VOIP, or you could look at the virtual PBX service at www.voipfone.co.uk. That service includes PSTN failover, ie if they cannot route to your VOIP phone, it will be routed to the landline.
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Can PlusTalk replace ISDN?

Thanks. WRT to 999 etc. I already have that issue with ISDN. If the wall box loses power, ISDN doesn't work. Also, if my PBX goes down, so does my telephony. Either way, my business landlines won't work. However, I have the PSTN line to which ADSL is attached plus mobile phones for ISDN. So, replacing my ISDN system with VOIP won't change much in that respect.

I'm trying to get a little more fault tolerance, so PSTN failover is a good idea. Thanks for pointing me at VoipPhone. FWIW, I'm toying with the idea of getting a second ADSL connection once my exchange has LLU so that I'm not reliant entirely on one provider for connectivity (this after a line fault effective shut down my business for three days last week!) This could even be a cost saver if I convert my existing ISDN line to PSTN.
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Can PlusTalk replace ISDN?

I think you can do exactly what you want with an Asterisk server. You can get inbound DDIs from voipuser.org (0845, 0870, 0844, etc) and shop around for outbound gateways (plustalk, sipgate, etc).

I recommend you spend a while evaluating the VoIP system once it's set up before cancelling the BRI connection though, just incase you can't get it to do what you want. You can also change the destination for the voipuser DDIs at a moment's notice, so you can easilly change between terminating calls to them on your Asterisk server or terminating the calls on your ISDN (or any other geographic number).
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Can PlusTalk replace ISDN?

Thanks Steve - much appreciated.

FWIW, until this thread I didn't know what Asterisk was - and I still have no idea how to set up an Asterisk server, or even what platform I'd need. I assume that I'd need to buy either dedicated VOIP phones or use an ATA for each existing handset (would I still get CLI etc on the displays of phones connected via ATAs?), that I'd need an Ethernet box within reach of wherever I wanted to put each phone, and that my existing 100-TX network would carry the VOIP traffic locally. Beyond that I'm "swimming in treacle"!

I've had a quick look at voipuser.org and voip-info.org but it seems like a black art right now. I'm going to work through the "getting started" section on voip-info.org, but can anyone recommend other "complete newbie" tutorials etc?

TIA,
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Can PlusTalk replace ISDN?

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until this thread I didn't know what Asterisk was - and I still have no idea how to set up an Asterisk server, or even what platform I'd need.


Asterisk runs under Linux (there is a Windows version I think but I wouldn't trust running a phone system under Windows). You might want to investigate Asterisk@Home, which I think gives a nice user interface (I've not used it - I use plain Asterisk with no nice stuff on top Smiley

You can also use (relatively) cheap ISDN cards with Asterisk to connect it to your BRI line - this might be something you want to do while migrating so the same phones can accept calls from both systems.

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I assume that I'd need to buy either dedicated VOIP phones or use an ATA for each existing handset (would I still get CLI etc on the displays of phones connected via ATAs?)


You can use either dedicated SIP phones or an ATA for each phone (or an FXS card - see below). Certainly with SIP phones you will get CLID, I imagine the same is true of ATAs. Unless you have some very posh phones I can't see a lot of point in an ATA though since you can get a proper SIP phone for around the same price.

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that I'd need an Ethernet box within reach of wherever I wanted to put each phone, and that my existing 100-TX network would carry the VOIP traffic locally


If you're using a SIP phone then you will need an ethernet connection to plug it into. The alternative is to put an FXS card (or several) in the Asterisk server which you can then connect to your normal analogue phones using the existing wiring, essentially turning the Asterisk box into a drop-in replacement for your analogue PABX.
Some examples of FXS cards:
http://www.digium.com/en/products/hardware/tdm400p.php
http://www.digium.com/en/products/hardware/tdm2400p.php

Prices on telecomms hardware seem quite variable, so shop around (using Froogle to find good deals is worthwhile)

It's also worth considering softphones in some cases - i.e. if you're only ever going to answer the phone when you're sitting infront of a computer (think: tech support people, etc, who need their computer anyway if they're going to pick up a call) then a hardware phone may not actually be needed, and you get the advantage of being able to copy+paste phone numbers directly into your softphone. I can recommend Ekiga and SJphone as good soft-phones.

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I've had a quick look at voipuser.org and voip-info.org but it seems like a black art right now. I'm going to work through the "getting started" section on voip-info.org, but can anyone recommend other "complete newbie" tutorials etc?


I can't really recommend any tutorials, but from my personal experiences I recommend you start off with the sample config files and fiddle with them rather than immediately trying to configure it all from scratch yourself.

And as always, ask away on forums and mailing lists when you hit problems - so long as you provide good information when asking questions (rather than just "it breaks" :-)) then you'll usually find the techies friendly and helpful.
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Can PlusTalk replace ISDN?

Thanks Steve,

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Asterisk runs under Linux ...

I was hoping that was the case because my Windows servers are doing enough already and I have a convenient Mandrake 10 box that's only hosting my development web server right now!

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You can also use (relatively) cheap ISDN cards with Asterisk to connect it to your BRI line - this might be something you want to do while migrating so the same phones can accept calls from both systems. [... and other related issues]

Unfortunately, my "computer room" is separated from the ISDN PBX (and the ISDN cable entry point) by over ten metres, several walls, and about 20 metres of Cat 5 (depending on how you look at it!) I suspect that I'd need to recable the POTS system to inegrate it with Asterisk, so when I do switch over I'll probably make a clean break.

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You can use either dedicated SIP phones or an ATA for each phone (or an FXS card - see below). Certainly with SIP phones you will get CLID, I imagine the same is true of ATAs. Unless you have some very posh phones I can't see a lot of point in an ATA though since you can get a proper SIP phone for around the same price.

I thought that it would cost me well over a hundred a handset to replace my current phones with SIP "equivalents". Perhaps I need to search around a bit more to find something a little less costly (any suggestions?)

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It's also worth considering softphones in some cases - i.e. if you're only ever going to answer the phone when you're sitting infront of a computer (think: tech support people, etc, who need their computer anyway if they're going to pick up a call) then a hardware phone may not actually be needed, and you get the advantage of being able to copy+paste phone numbers directly into your softphone. I can recommend Ekiga and SJphone as good soft-phones.

Thanks - I'm toying with the idea of soft phones - I spend most of my time at my desk. However, I have several computers connected via a KVM and Murphy's Law says that I'll be looking at the wrong machine when a call comes in! Perhaps a USB solution would be better. I assume that Asterisk doesn't care whether your phone is a hardware device, a software device hosted on a workstation, or something between (e.g. USB).

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And as always, ask away on forums and mailing lists when you hit problems - so long as you provide good information when asking questions (rather than just "it breaks" :-)) then you'll usually find the techies friendly and helpful.

Thanks - I'll try not to be too much of a PITA!

ATB,

Geoff
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Can PlusTalk replace ISDN?

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Unfortunately, my "computer room" is separated from the ISDN PBX (and the ISDN cable entry point) by over ten metres, several walls, and about 20 metres of Cat 5 (depending on how you look at it!)


Well you can run ISDN over cat5 Smiley

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I thought that it would cost me well over a hundred a handset to replace my current phones with SIP "equivalents". Perhaps I need to search around a bit more to find something a little less costly (any suggestions?)


A quick look at SipGate shows a basic SIP phone at 45 quid:
http://www.sipgate.co.uk/voipshop/grandstream/grandstream_bt-101
It obviously depends on what kind of feature set you want though. I've recently bought a UTStarcom F1000G, which is an 802.11g SIP phone so no wires needed. Smiley

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Perhaps a USB solution would be better. I assume that Asterisk doesn't care whether your phone is a hardware device, a software device hosted on a workstation, or something between (e.g. USB).


A SIP phone looks the same to Asterisk whether it's a stand-alone device or a piece of software on your computer - either way it's got an IP address and accepts SIP connections. I've not really looked at USB handsets, but the impression I got was that they're just USB sound devices and appear that way to any software - so you'd still run a softphone on the PC and just tell it to use the USB device for sound input/output.
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Can PlusTalk replace ISDN?

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A quick look at SipGate shows a basic SIP phone at 45 quid:
http://www.sipgate.co.uk/voipshop/grandstream/grandstream_bt-101
It obviously depends on what kind of feature set you want though. I've recently bought a UTStarcom F1000G, which is an 802.11g SIP phone so no wires needed. Smiley

Thanks - the price is right but I'm not sure it will do what my current phones will do:
  • Speakerphone with on-hook dialling
  • Redial with scrolling selection of last ten distinct dialled numbers
  • Built-in directory with 99 entries
  • Incoming caller log (last ten distinct callers) with the ability to return calls.
  • etc.
I suspect that I'll be able to use software to do much of this if I choose a softphone/USB for some handsets. That said, I wonder whether the BT-101 can work with Asterisk to at least access a central directory / caller log?

I really do appreciate the help that you've given me - VoIP is now more of a grey art to me than a black one!

Thanks again,

Geoff
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Can PlusTalk replace ISDN?

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That said, I wonder whether the BT-101 can work with Asterisk to at least access a central directory / caller log?


Unfortunately, SIP doesn't support directory services like that Sad
What phones probably should do is have the ability to query an LDAP server for directory lookups, but I've not seen one that's got that ability.

Another option is to put your directory into a web page. If you're using a softphone then you can get it to dial when you click on a SIP URI like sip:foo@example.com and you can also get the web server to trigger Asterisk to dial both your phone and another number at the same time and bridge them (i.e. you click on a link, you phone rings, pick it up and it automatically dials the number you clicked on). Probably not as nice a solution as having the phone support a central directory natively, but it's a possibility.

That said, I haven't really looked into directory services so there may well be a better way of doing it that's already common knowledge. Smiley