If it's about VoIP, SIP or Internet Telephony but it doesn't seem to fit anywhere else, post it here.
By AlbianComms

OK, I know this is probably a cheeky thing to ask, but has anyone out there got a simple diagram/schematic to show what hardware I need to to set up an office using the voipfone PBX system.

I understand it from the set up of my own office, with one only phone plugged into my router. But I'm not too clear on what I would need to set up an office with around 5 extensions.

I'm also worried about bandwidth issues. Will using all the phones over the broadband affect the speed of surfing the Internet/sending large e-mails, etc, and how much bandwidth is generally needed. This information will help me choose a business broadband provider. Any recommendations in this area would be gratefully received.

If there's one modem/router set up, how do I connect the five ext. phones to the main router, plus the computers? Or do I need some sort of server? Is the solution the kind of phone that has two ethernet ports, one to plug into the PC, and will this really be able to surf the Internet, send faxes, and carry on voice calls without any 'choppiness'? And what about incoming faxes?

Are there restrictions to the length of cabling before you start losing quality, and is there specific cabling I need, or is just the same stuff I use to connect my router to my Mac/PC? Or is this a really dumb question?

You see! I'm totally at a loss. I get the general gist, but having the opportunity to set up a new office from scratch, I want to make sure I get the right equipment, allowing for the business to expand. I may get people who want different set ups, I suppose. But I'm guessing most will have a PC/ Laptop at the desk. What are the adaptors like for normal phones, are they feasible solution? And how normal a phone are we talking?!

Is anyone running the system on wireless, if so, how's that going?

Any rough diagram of how everything connects together (in principle) would be much appreciated. I need to get some idea of the cost to set it up, and the budget is not too high.

I've never really had much to do with phone systems before, or setting up a network larger than my home one (Mac + PC), so be gentle!!


By c0d3r

I don't have a schematic as such - however the setup is very straightforward.

You will need a router connected to your broadband - we would recommend a Draytek Vigor - they are very stable and reliable, and also allow you to prioritise traffic - so you can give VOIP traffic the highest amount of bandwidth to ensure good quality calls.

I will leave it to someone else to comment on the bandwidth requirements of 5 phones - personally we have 3 phones connected with no visible degradation of quality.

The draytek routers have 4 network ports - you can connect an additional hub to this to give you as many more ports as you need - each phone / PC will need a port - although with some phones you can connect a PC to the Phone.

In theory there will be little degradation in quality for cable lengths upto 300m - which should be plenty for your needs? The cable is identical to that used to connect PC's to the router.

Normal phone adaptors simply allow you to use a standard BT analogue phone with a VOIP system so are ideal as a cheaper option on startup - although most customers we deal with like to have display phone and extra keys etc.

I'm afraid we have no experience of using the system on wireless as yet.

If you would like to discuss anything further on the phone or in person, message me. We are based in Cheshire and would be happy to help.

By VoipIT
Simple schematic? Yeah, plug the phones into a switch/router ...

No, it's not that simple. The wiring schematic is, but there are other factors. We've got 25 extensions, so we've been down many of the avenues you're worried about! To take the ones you've mentioned ...


You need to work out the likely maximum number of concurrent calls. You mentioned five extensions, so let's say you might have up to 5 concurrent calls. Each call will use between 40kbps and 100kps of bandwidth, depending on the Codec you've told the phone to use. The g711 codecs use about 100kbps for each call, with great quality. The GSM codec uses about 40kbs, with quality similar to that on a GSM mobile phone.

You need to look at the upstream bandwidth of your internet link. For example a maximum upstream bandwidth of 256kbps would allow (in theory) six concurrent GSM calls or two g711 calls.


In practise, voice calls are unlikely to affect the performance of your network (it's more likely to be the other way around), due to the limiting factor being the upstream bandwidth. You're unlikely to be saturating your upstream bandwidth with regular traffic unless you're hosting a website or uploading large files.

Ideally, if bandwidth is short for any reason, you want calls to take precedence over other traffic - otherwise you'll get dropouts or dropped calls. A router than implements QoS will help in this.

Physical Connection

We have two broadband connections, one for VoIP and one for regular internet usage. That way, neither impacts on the performance of the other, but if one failed, we could manually route both over the same link temporarily. All share the same physical wiring, and both router/modems are connected to the same switch. VoIP phones are setup to use one link as their default gateway, and all other devices are setup to use the other link.

You don't need a server ... but you do need a "switch". This is a device that the network cables from all your devices (phones, PCs etc) go into, together with a network link from your broadband modem.

The Snom phones do have a built-in 2-port switch which means that they can share the same physical wire as a PC, but this isn't ideal. It works - but it means that the PC and phone are sharing the same bandwidth, and that if the Snom phone is off (or rebooting) you can't get internet access. We use this, but only where we can't get an extra cable to a desk for some reason.


Use a quality phone. We tried the Cisco phone (not ATAs) and were very disappointed. The Snom/Elmeg phones are superb though. Avoid using softphones (X-Lite or SJphone) if possible - there's just too many variables involved (PC CPU load, other software) to be able to be certain of good call quality.

Incoming faxes

These arrive by email in your inbox - there's no problem of bandwidth contention.

Cabling length

There's no requirement on cable length over and above what's required for any network connection.


One of our home workers has tried it, and has had nothing but problems. VoIP is pretty sniffy about latency and dropped packets, and wireless is prone to both of these issues.

New office setup

If you're planning on relying on VoIP, I'd recommend that you have dual broadband connections - one with BT, one with another provider. That other provider should be using different equipment to BT - ideally Virgin Media cable broadband, or if it's not available in your area, another ADSL provider who uses LLU (Local Loop Unbundling) which means that they're using their own private equipment in the BT exchange.

I'd also recommend that you have at least one regular phone in the office, attached to the regular phone line that comes with ADSL. You need this in case of network failure for outbound and inbound calls, and arguably need it for 999 calls. Set up the PSTN failover feature of the Voipfone system to pass calls over to this line if the network link fails.

You might want to have this phone be a fax/phone ... although you can take incoming faxes by email, there's (as yet) no Voipfone solution for outgoing faxes, so you'll need one yourself.
By GoofyCyborg
To summarise all that great information:

1. You need a standard RJ45 (cat 5e) cable from your router to your VoIP telephone (unless you use a softphone of course). Some telephones, the Snom is one, have a socket for connecting your PC's connection too so that if your phone is near your PC you only need one cable back to your router.

2. If you have a standard domestic router it will have 4 ports to attach your PCs and phones to. If you need more ports than that you can buy switches that add ports 4, 8 or 16. These are very cheap (4 port switches are about £25) and work well. If you have an office at a distance from your router just run one cable to it and attach a switch at the office end.

3. Wireless allows you to do away with cabling but at the expense of some quality although things are improving quickly.

4. As for costs - routers are about £70-100, extensions are £1 per month, 4 port switches £25, broadband £15-30 per month depending on the service, telephones and adapters between £50-200 depending on choice. You can do cabling yourself just buy made up cables for a few pounds each depending on length.

There's nothing like DIY for getting a real understanding of how stuff works!
By AlbianComms
Hi folks,

Sorry for the delay in responding... I've been trying to soak in all the information :shock: Thank you all so much, I don't think I've been left with any questions, apart from which VOIP phone I'll be buying for myself.

I'm going to try to draw up a schematic of what I think will serve the client's requirements. Unfortunately, haven't been able to get into the office yet, so will have to wait... tum-te-tum!

No doubt I'll be back for some more advice. :oops:


By c0d3r
If you're just about to move office, then you may not have a lot of time for fixing snags.

If that's the case, I'd recommend you go with a tried and tested solution. Anything else, and you run the risk of having several weeks of trying to make it all work together!

Having two separate ADSL connections gives you some degree of failover )(though not if they're with the same provider), but more importantly clearly and cleanly separates the traffic. For your size of setup though, QoS will be likely to be good enough for traffic prioritisation.

For contention ratios, I've yet to hear of anyone suffering from this during office hours. The peak times for contention problems start around 5pm and go on to about 9pm - when folks have come home from work or school! Also, bear in mind that others are usually contending for downstream bandwidth, not upstream.

When making bandwidth calculations, do take Codec selection into account. If you use the higher quality g.711 codecs, you'll get 2 maybe 3 concurrent calls on 256Kb/s upstream. If you use the slightly more agressive GSM codec, you should get up to 6 concurrent calls.

On forwarding - when you forward a call, you are then out of the loop - the media path (ie the conversation) gets routed direct from it's VoIP starting point to it's VoIP endpoint. If it's an inbound call that you redirect to your factory, then it will be using none of your bandwidth after redirection.

I wouldn't splurge on a Cisco, but I would change your router and firewall to one of the Intertex jobs. These have QoS and are SIP-aware, resolving a lot of niggly problems. Your current switch should work fine with this.

If you are on an aggressive timescale as I'd guessed at the beginning, then I'd strongly suggest you use Snom phones. There seem to be much fewer problems amongst Voipfone users with a Snom than other types of phone.
By andrew@mcpear

Just a quick question on bandwidth, I can understand a call, incoming or outgoing using bandwidth on your broadband connection, but a call from one extension to another in the same building, subnet ect, once the call has been setup, does this use any bandwidth on broadband, or is the call routed internally with no external data transfer?

Basically, if I have 2 external calls, can I also have more internal calls?

Hope that makes sence!!

Thanks very much.....

By c0d3r
One of the counter-intuitive quirks of the current Voipfone infrastructure is that extension-to-extension VPBX calls within the same LAN actually use *twice* the bandwidth of a regular incoming or outgiong call.

It's because the media stream (ie the voice traffic) still goes through Voipfone.

I'm not entirely sure why they do it that way, as it's a bandwidth hog and uses up their CPU time too.

You need to factor this into your bandwidth calculations when choosing codecs.
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