Best way to create an internal phone system?

So, this may seem like a ridiculous question, but I’ve been asked to do this and am thinking it through - just seeking help and opinions.

We would like to set up a phone system between three parts of a building. These need to be able to call each other and do basic office functions (hold, transfer, etc. if possible) but at the very least they need to be able to call back and forth.

The idea is that it will give students an opportunity to be in an office setting as employees, answering incoming calls, transferring, taking messages, etc. This would be used as sort of a lab setup for them to do more hands on work.

I have looked into IP phone systems, and I remember seeing it setup as a setup that a HAM guy I know did, where he used wireless routers, old school phones, and IP numbers for calling. Are there some other options for this? I have less experience than most in this - I’m the librarian - but I’d be glad to help out. Any information might be helpful.


Are you determined to build it yourself?
Centrex is a phone system set up and managed by at&t. It works pretty well for small applications like what you describe.

Or you could buy a small PBX:

If you’re willing to do a bit of tinkering, you can build an excellent PBX with a spare PC, a line card, and Asterisk, which is free and has a good community.


Oooohhhh, that looks fun!
Have you guys actually built a system with it? What’s the learning curve like?

There are many inexpensive PBXs that will use ordinary phones or fancy feature phones. I have two Panasonic systems here, in crates.

There really isn’t any good reason to go to the fragility, expense and maintenance requirements of VOIP or server-based phone management for a basic internal phone system. (Or even a not-so-basic one; the Panasonic systems have hundreds of features.) A low-end PBX system will do everything, reliably as Ma Bell used to do it, without maintenance or PC hassles, and cheaply.

I ‘vass dere… at de beginning’ of intelligent telephony. I have had industrial-grade PCPBXs in my house and small offices. I learned to respect the good, solid, old-school stuff a lot.

ETA: A 4-line voice card of quality worth having, by itself, will cost more than a secondhand PBX system with phones.

Thirded. If you use a VOIP/SIP Trunk provider, you can do away with the line card (I use A bit of a learning curve, but that good community is indeed good. Lots of power and lots of fun.

Have you considered just getting a stack of cheap, prepaid cell phones?

I had look at a PBX but the cost was a bit more than would be helpful. Ideally, the cheapest possible option is the one that we will go with. The idea of using Asterisk is great, and exactly what I would probably do, but when I was describing it to another person involved, it hit me like a truck…

We have a phone system installed already. Some phones have certain abilities (outside calls) and some don’t (from what I know). Why don’t we just add in 5 more extensions and not use those for anything but in this setting? Well, it’s a place to start anyway before we try to make a secondary system solely for this purpose.

Prepaid phones would eat up minutes. Oddly enough, we don’t want these phones to do too much. At the same time, I’m thinking they could be useful for more than what other people are intending. For example, their thought is for medical assisting students that need to learn office procedures, the phone would be used for actual roleplay/practice/etc. I could see our career services guys doing practice phone interviews with students, instead of just mock in person, for example, would be a decent use.

Unfortunately, I would be excited to completely dive off the deep end and start rebuilding a tower for this tomorrow. I’m probably going to have to submit a few ideas and see what IT decides to do, as it is not similar to cataloging books and providing reference services…

A new PBX and phones would be absurdly expensive, given the relative investment.

A used set in good condition can be had for as little as $200.

Other than the “of course you start with a PC” mindset and the desire to tinker with software, what’s your time, money and upkeep budget for this “basic internal phone system to let some students talk to each other”?

I looked at used also but if they could do it with the system we already have, it would have very little cost. I’m thinking, for example, if our system could handle 20 internal lines, and we use 8, let’s add a few and just not use them for anything else.

Myself, I know that the actual time investment would be large, but I also think it might be fun to tinker with, so I know personally I would go out of my way to do that. The big problem is that the upkeep would be annoying. Again, I would give it a shot, but I’m a librarian. Say another library hires me in a year, someone would have to pick up where I leave off and figure out what my homebrew system was doing. That would be a mess long-term.