General VOIP question-Please read

Just as a pointer I would look into using Asterisk as a PBX

I used it with ViaTalk and a handful of phones for my home and it was the easiest to set up with of all the VoIP providers I tried it with. You can also look at my review at which is residential, but they do have plans for business as well.

Do you have a PBX already, or do you lease 200+ lines from the phone company?

What's your objective? Lower monthly costs? Ability to connect phones (or adapters) to your IP network?

In general, it's probably a good idea to look at connecting phones to your IP network (standard phones with a terminal adapter or actual IP phones). I recently had a look in the wiring closet of our building. Hundreds of CAT5 cables just for phones, cross-connected to analog loops via BIX blocks. Ugly!

I would NOT recommend any solution that travels over the public internet. Start by talking to your local phone company and ask what types of interfaces can be directly connected to their network (T1, SIP etc.).

-Pat

Rob wrote:

We do have our own PBX but it is an old system and we are looking to upgrade it. Eveyone has CAT5 for their desktop connection, I am not sure about pros and cons to share this data line with IP phones. we have 200 people and about 40 lines in different buildings but all local, With our structure do you think that we can save money if we go with VOIP? Do you think that the maintenance would be cheaper and easier, is that going to be more work for IT people, do they need to take special training? Is it ok to use the existineg phones (with some basic options like forwarding...) with VOIP?

Sorry for too many questions-Rob

We have a Cisco system, router and phones. Using mainly Cisco 7960 phones (6 button) with a few 7940's, (2 buttons). Because it's VoIP, there is a lot of flexiblity in the way they are setup. Although our office is in Dallas, we have one person that works up in Oklahoma and it's just like she is in the office.

We have very few problems with the phone side. At this time though, I would not recommend going with a virtual fax system. I've been through

3 different VoIP companies and each one had problems with that type of system. I just converted us back to Venali fax (like Efax) for incoming and outgoing.

Paul Heckmann VP Ops/IT CreditAnswers

A bit of background:

Your current system is analog. Basically, there is a pair of wires between each phone and the PBX, working somewhat like a bi-directional speaker. The PBX takes the analog information from each phone and converts it into a continuous stream of digital information (64 kilobits of bandwidth for each phone conversation). This continuous stream has to be handed over to the phone company, most likely as one or more T1 trunks. A T1 is basically 24 of these continuous streams.

So, each phone is sending/receiving an analog waveform and the PBX makes sure that each conversation has a nice (dedicated) 64 kbit/s continuous digital stream to the phone company. The entire phone company network is basically a big mesh of these 64 kbit/s dedicated connections, resulting in nice, clear conversations.

Enter VoIP:

As with existing digital telephone switching, VoIP also takes analog voice traffic and encodes it into digital form. The two main differences are: 1) voice traffic is digitized, not into a continuous 64 kbit/s stream but into individual IP packets and 2) the voice traffic is converted into IP packets (digital form) right at the phone (if it's an IP phone) or the terminal adapter (TA) that the phone is plugged into.

From the moment the information leaves the phone (or TA) it exists as IP packets and can travel...somewhere. In your case the first stop for /somewhere /is the PBX. That's the easy part. Everything on the enterprise side of the PBX should be clear and distortion free, provided your network has lots of bandwidth.

Of course, you want to be able to switch this nice, clear, distortion-free IP voice traffic out of the enterprise and into the public network. This is where I think you need to sit down with the local telco and ask them what kind of network interfaces they support and price them out. I think you want your phone traffic to go direct to the telco rather than over the public internet. At the end of the day, the PSTN (public switched telephone network) is still essentially a big mesh of 64 kbit/s pipes, so most external calls will eventually be carried in this form. VoIP providers like Vonage punt your IP voice traffic through an intermediate company like Allstream to reach the PSTN. You don't have any control over the quality. /Somebody /is going to convert your IP voice traffic and inject it into the PSTN. That somebody may as well be you, and it should probably be done right out of the PBX.

I've focused mainly on voice quality here. If you're looking for the ability to make unlimited long distance calls for a fixed monthly cost then the local telco may not be your best option. You should still talk to them, but at the same time you may also want to talk directly to a company like Allstream about handling your IP voice traffic out of the (new) PBX.

I'd also recommend that you talk to a VoIP gear vendor like Cisco, who can sell you the IP phones and PBXes. They will also tell you what the best options are re: how to connect to the outside world.

There are lots of ways to begin your journey, but it's definitely the right direction to go in. My employer (large government agency in Canada) is going to a Cisco IP phone solution. I'm pretty sure they're going to have a gateway from the PBX direct to the local phone company.

-Pat

Rob wrote: