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On Mon, 11 Apr 2011, raymond.knowles@xxxxxxxxxxxxx wrote:
"for whatever reason, that didn't work." The problem with conventional telephony is the voice response is very close to immediate. With VOIP, there are small delays in the A to D and D to A converters, which make a conventional conversation much more difficult.
Hmm... So bear in-mind that I run a VoIP/Telephony company as part of what I do for a living .... (so I may appear biased) ...
All I can say is that you must have had experience of some really crappy VoIP systems.
My experiences and that of my customers is that you really can not tell the difference between a working VoIP system and traditional telephony. (Other than it generally sounding better!)
That's not to say that there are issues, but they're all well known and understood and when implemented correctly they're simply not noticeable.
Nottingham University had a similar problem when they converted their telephone network to VOIP. For anyone dialling in to an extension, the delays are a serious obstacle to conventional interactive conversations.
VOIP may be cheap, but it is also nasty.
Sorry, but I really don't believe this at all. It's not my experience an I really can't just sit here while one person tell me VoIP is nasty.
Nottingham may well have had difficulties with their system - a lot of big installations do - but then, they're using big proprietary systems with expensive licensing... Want local examples of who use VoIP? The Eden project. They have a big Cisco installation. Paignton Zoo have an asterisk installation, as does Netwon Abbot Racecourse (I think). 118118 Also uses VoIP (asterisk), as do a good portion of call centres. Exeter university too - and while they have had issues, lag on calls doesn't seem to have been one of them.
And who says VoIP is cheap? I've given examples of free VoIP, but do you know why they're free? They're free because they route the calls out of the UK via VoIP via one European country, then route them to another country via VoIP, then route them back into the UK... I don't sell these free systems, I charge real money for my VoIP systems, and give my customers real phone bills. You get what you pay for...
Also most of the indirect prefix diallers use VoIP internally to do the call routing.
Skype is obviously VoIP, but who knows where your call is being routed then - they use the goodwill of "supernodes" to route calls in situations where both endpoints are behind NAT and a direct connection isn't possible.
And, I think you've forgotten that the A->D->A conversion happens with traditional telephony too - analogue from you, over X miles of Y year old copper to the exchange where the AtoD conversion takes place, then it's then carried digitally over the BT network and DtoA'd at the far-end. That takes time too. Those conversions are identical to what happens in VoIP land too - we use the same CODECs and algorithms to do the conversions, although we do it at source (the phone on your desk) rather than X miles away at the exchange. (ISDN does it this way too)
What is bigger in VoIP is transmission delay - and that's down to the IP overhead and basic link ping time, however, that's typically under 35ms each way and at those times, it's impossible to detect. Round trip times of up to about 120ms are very usable without noticing that it's happening. More than that and it starts to become noticeable, but it's no worse than an old-fashioned call to the US or Australia. Some of my clients even use VoIP over 3G networks where the ping times there are often well over 100ms.
And here's an experiment for you - call your home number from a mobile phone and have both in the same room. You'll hear the delay when the person who answers speaks (you'll hear them before you hear them through the phone), and it may well make having a conversation difficult, but go somewhere where you can't hear the other person and you'll notice no delay at all. The delay over a mobile network is typically more than VoIP.
So if you're not convinced then I can setup some demos for you - maybe at a LUG meet, or whatever.
Gordon -- The Mailing List for the Devon & Cornwall LUG http://mailman.dclug.org.uk/listinfo/list FAQ: http://www.dcglug.org.uk/listfaq