In the early days of Ixis, we ran the open source PBX Asterisk in-house. At this stage we didn't have servers coming out of ears like we do now and ran it from an archaic pentium 3 that was literally shoved under a desk.

Whilst this worked and got us by, it was far from ideal being a single point of failure. We also spent much more time than we should have on the initial setup and learning Asterisk, and were still only just scratching the surface of it's full capabilities.

So we moved to a hosted Asterisk setup from Gradwell. For just £8 per month we got an external 01x phone number and 10 internal extensions, which was more than adequate as we only 4 staff at the time.