Getting feet wet but haven't taken the plunge yet, need advice.

SIP has come a long way in the past 4 years, Your hardware is good, but I would do a test install first to see if you are going to need any drivers that are not in the tb install, do you have the space for a TDM card(s)? (this is what you will use t for the PSTN lines), how many Analog phones are you going to use if any?

When you are going to look @ Analog card(s) I would look at the Sangoma cards(kinda pricey) they will give you the expandability you are looking for, but of course Digium and Rhino are also the top leaders. If you are worried about echo I would get the cards with hardware echo canceling.

I would also stay away from the Linksys phones and go with Aastra phones as they seem to be the best of the bunch for the price (polycom is a close second(for me anyways).

for the SIP I would look @ vitelity.net they seem to one of the better ITSP's out there( good pricing) and I am sure there are better ITSP's out there I just have not found one(yet).

If you would like to due some testing PM me and I will setup an Ext for you to try out.
I use only SIP with Aastra's 57i, 480i CT and Grandstream's GXP2000 and GXP2020.
(I would not recommended the Grandstream phones as they do not have direct tb support (at least the GXP2020 does not).

Of course this is all just my opinion and I am sure there will be other things that I have over looked that others will pick up on.

Did you load the software on a computer and try a couple of soft phones? That's the best place to start.

Make sure when they are wiring the building that proper cable is installed. You need tested and terminated Cat5 cable. One drop for the computer and one drop for the phone. If you want to use a single drop you will need to use an even more expensive managed Ethernet switch. I hope you have not included wiring in your budgetary estimate.

VoIP quality is highly dependent on the quality of your Internet connection and other factors. What part of the word are you located in (if US what state?). What type of Internet connection do you have?

This is always a great idea. Gives you the best of both worlds.

It is very simple. You sign up for the service and the provider gives you a login/password and server address, possibly a few more settings. These are programmed into the trixbox. You can then router inbound calls and send whatever call you desire to the 'trunk'.

As mentioned you just need to add hunting to the lines you already have. The phone company will then send your inbound calls to the first available line.

The system has software echo cancellation this is sufficient for all but the worst phone lines.

This is more than enough server. It is also the sweet spot in used servers. Make sure you get a 2U server for expansion slots.

Do you really need 10 lines? Is everyone going to be on the phone at the same time? If you could get away with 4 phone lines and the rest SIP for overflow you would save some money.

If you could save some money on recurring expenses you could free up more for the initial costs.

Here is a rough budget:

1. 10 - Aastra 9143i $150/ea = $1500.00
2. 1 - Used HP DL360 Generation 3 server = $500.00
3. 1 - Linksys 24 Port PoE switch = $550.00
4. 1 - UPS = $150.00
6. Total $2700.00

   Not far off your original budget. This is 1/4 of the price you would pay for an old style "key system" with voice mail.

   You also should budget for consultation with a professional to make sure your installation goes smoothly.

   Good luck....Scott

Yes, it's actually better, they will have two buttons on the phone with their extension and be able to 'broker' or switch back and forth between calls. They can even have ad hoc conferences.

Aastra 9133 are your best choice in that price range. The 9143 have been introduced however if you are price sensitive you should be able to get a deal on the 9133. The difference is the 9143 have the ability to run custom applications using XML.

Rollover simply forwards the call to the first open line. It is a service from your phone company.

Depends on the complexity of the building. Between $40US and $100US per drop. You will need to have the wiring installed no matter what system you choose.

That is great upload speed. You can easily handle the 5 concurrent SIP calls assuming you do not have heavy upload usage from your users.

Hunting and rollover is the same thing.

Yes, sorry I forgot to add that.

CE would also do the trick. You should try them all before making a decision.

It will probably be twice the recurring cost of the POTS/SIP configuration. Would not hurt to get a quote from a few local providers.

Scott