Friday, 30 March 2012

My Projects: My very first commercial project - VoIP

This is the first post in the "My Projects" series, and I decided to start with my very first project completed in a commercial organization.

It was the beginning of 2004 and my first (big enough) idea at the new place was to improve the telephony. Since pretty much time has gone, I cannot remember all details, but the main is the idea.

What we had:

  • 1 main office with Panasonic KX-TD500 with about 8 external lines and about 150 extensions.
  • 2 big branches with some other PBXes
  • about 5 small branches with or without dedicated phone lines.

We didn't have any kind of IVR implemented, so any call to the office was served by two operators and forwarded manually. The main problem was that internal company calls was made also via PSTN, and our customers claimed quite often that they can't break through the busy lines.

The second problem was that even two operators at the same time cannot serve all flow of the calls, so some percent of inter-company calls was dropped, and of course there was quite important calls also.

The same problem was experienced by our two branches. Number of the phone pick-ups was about 85% from the calls initiated! 1 of 6 of our users or customers got "busy" during the day!

Along with that, all branches were connected to the main office other by SHDSL lines (double in some cases) and almost wasn't utilized (RDP traffic only).

As usual: "Please do cheap, good and reliable".


First we started with pretty cheap VoIP gateways from Dynamix. We had very good impression of their gateways with FXS port, and even installed them in 3 or 4 branches. But when we get to the next step of our project (integration with the existing telephone network) we have found out that FXO gateways connected to PBXes generates unacceptable echo. Support from Dynamix couldn't help us with that, so we had to resign from their hardware and started to search for another brand.

Next one was Planet. This time we've got VoIP gateways with FXO and FXS to test simultaneously. And this time tests was successful. We began to install our solution step by step, and in two month we have the following configuration:

  • Main office - Planet VoIP PBX (don't remember the model, but something like IPX-2000) with 2 modules 4 ports each connected to Panasonic TDS-500 to extension ports.
  • Big branches - Planet VoIP h323 gateways with 4 FXO ports connected to PBXes to extension ports
  • Small branches - Planet VoIP h323 gateways with 2 FXS with phones connected directly to them.

Gentoo  linux with GnuGK was used as a H323 gatekeeper (SIP wasn't really popular then).

The IVR has been configured on the Planet PBX and was also used for the external incoming call. There was a standard invitation like "Hello, this is company ABC, please enter extension or wait for an operator". But this made our users enormously happy.

After the Project was completed 100% of all calls initiated reached the target extensions or the operator.

Bills from the public telephony provider lowed by 2 (!) times. All new equipment payed off in several month.

Side effect:
One of operators was raised to the Office Manager, since there was no more need to hold two operators at the same time.

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