Hello Francis, My office build is the same as yours. 15 or so extensions, low traffic 100MB network, and a desire to have a phone system that uses VoIP. I have my system working as a PBX just like you would. I use two TDM400s for my 8 POTS lines and Polycom IP 500 phones at the desktop. I also tested with the Grandstream phones you suggested. SO, we have the same system requirements so here are the answers as I have found them for my implementation....
Voice quality on the SIP based phones has a lot to do with the codec you use. The lowest compression codec is uLaw and that is what I use since we have tons of bandwidth to spare. Also, my HP switch has COS (class of service which is like QOS) so I can prioritize the packets coming from my phones over the standard network traffic. Even without this switching feature turned on, performance was great. The phones themselves play another role in the quality. Grandstreams are pretty good and I have only used mine for testing so I will not disparage them. However, the old saying stands. You get what you pay for. Raising your phone budget from $85 to more like $150-250 will get you a phone with more features and greater expandability in my IHO. However, you can still do great things with the cheaper Grandstream phones and still have a system that works very well. IT is all up to what you can spend and what you need. Google the archive by putting "site:lists.digium.com" in front of your search string (no quotes though). You should see some good info on phones. Latency is gonna be there on any network. However, on my network (which is just like yours) the latency is very very low. We are talking 20-40ms tops and it is completely unnoticeable when using the phone. The only problem I have had at all has been with occasional echo. It does not happen often and it usually takes about 5 seconds for the * box to train up and remove it. Most of this seems to originate in the fact that I am using POTS lines. The solution that uses a T1 PRI has better features and I think it has less echo potential. However, that would not work for me since my T1 provider wanted to make me pay 6 grand to switch to a PRI from my standard data T1 with POTS. Just some food for thought... I have been a VoIP user for about 1 month after spending another researching what when where how... So, we know I am not an expert... but as a fellow user and new VoIP initiate, I can tell you that Asterisk is a phenomenal product for SMB level offices like yours and mine. When I compared it to a PBX system of comparable power, expandability, and feature set, Asterisk won easily since the only real cost I have had was for my phones. I have my system in place for around 3000 dollars and it is competitive with all the 10K dollar solutions the vendors threw at me plus it has an undeniable advantage in upgrade path. All upgrades to the system are free and the sky is the limit to what you can build using the framework that all the * gurus have built into this system. Not to mention the fact that if anything ever goes wrong with the server, I can have a new one in place in under and hour. Try that with a PBX when some proprietary part goes belly up. You could wait days potentially. My $.02. Hope this helps. Cheers, Wiley -----Original Message----- From: Francis Augusto Medeiros [mailto:[EMAIL PROTECTED] Sent: Saturday, August 14, 2004 1:08 PM To: [EMAIL PROTECTED] Subject: [Asterisk-Users] Help - is voip good for in-house calls? Hi there everyone! I work at an office where we plant to have about 12-15 phone extensions. Costs of PBX are cheaper, but they are not expandable and, as the office is brand new, I want to use all modern stuff. My question is: if I buy 12-15 Grandstream Budgetone 101 phones, and install and asterisk server, as well as a Digium TDM400 for POTS access, will I have the same voice quality and standards as a PBX-only, with "traditional" phones? Or should I go all the way to Digium's TDM? Or should I forget the whole thing and get a traditional PBX? ;) My concerns are most latencies. Our network will be a switch with lots of ports, all 100mb/s, with VERY low traffic. I've read lots about voip, and I'm quite impressed with it, but most case studies show voip being used to interconnect offices. My case is different - I want to replace a traditional PBX to handle in-house phone calls, either from room-to-room in the same building and room-to-POTS. Any comment, help, tip or link would be greatly appreciated! Yours truly, Francis _______________________________________________ Asterisk-Users mailing list [EMAIL PROTECTED] http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users _______________________________________________ Asterisk-Users mailing list [EMAIL PROTECTED] http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
