IMO I prefer Grandstream phones because of the flexibility of the software. Linksys phones are also quite good.
Using G711 codec each call will use about 84Kbs of bandwidth so dividing this into the max upload speed will approximate the maximum number of concurrent calls that is possible. So if you want six concurrent calls you will need at least 84Kb/s x 6 = 504Kb/s bandwidth. Most Internet providers can offer 850Kb/s so the theoretical limit is about 10 concurrent calls (but lucky if you get 8) When considering the requirements of your proposed system however one should take into account the type of business. As an example Call Centers need a high ratio of lines to extensions ie. > 1 : 1 while a typical insurance office might be somewhere closer to < 1 : 3 or 6 lines for every 18 extensions. Since were on this general topic it is worth comparing the internet using SIP protocol with more traditional stuff. PRI's cost about $48 per line with (roll over lines costing about $32 each. A T1 trunk can handle 23 channels concurrently however they are quite expensive depending on location but just for argument sake it cost $460 per month... it works out at $20 per line per month (not too bad). The break even point to justify a TI is about 15 PRI lines. Asterisk makes the break point much lower in terms of hardware IMHO about 11 lines is the break point. Lastly, PRI's and T1's have a much longer MTBF so some people hedge their bets having some analog lines that can keep the client in "Business" should the internet go down or your ITSP have an outage. Hope this helps your decision making... H On Thu, Feb 2, 2012 at 4:34 PM, Dean Yorke <[email protected]> wrote: > Hi All, > > Can I get some feedback on a couple of things? > > 1) What phones are people using these days. polycom, aastra cisco. > 2) What phones are best? > > 3) virtual PRI vs SIP Trunking. What's the difference or are these buzz > words. > > 4) suggested data throughput for 6 lines. DSL or larger? > > Thanks > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [email protected] > For additional commands, e-mail: [email protected] > > -- * Henry L. Coleman * *VoIP-PBX.ca Dragnetics.com <http://dragnetics.com>*
