pbx/pabx project sites

[nolram]

hello everyone! i need to search for any pbx/pabx projects in the web, but i could hardly find any...i need ur help, pls help me find web links to projects that i can try...thanks.  :D

[gogo2520]

Sorry I can't help you I don't even know what pbx/pabx is. What are they?
                                              gogo

[audioguru]

Hi Nolram,
I installed, programmed and fixed pbx and key telephone systems.
The very old ones used stepper switches and were simple. The last key systems I worked on in the '80's used a processor in each phone, on each card then an overall processor.
Customers' offices were used as beta test sites for new models and they frequently messed-up.
One new model had an intermittent system reset, dropping all connections. I discovered that it occured when an incoming call rang a line at exactly the same time someone used that line to call out. The Japanese engineers couldn't reproduce the problem in Japan, so came over here to see how I do it! They still couldn't get the timing syncronised like me.

Those systems were 20 years ago and were very sophistocated. Modern systems are even more integrated, using ICs designed for them. I don't think a single person could design one, it would take a team of emgineers.

In the '90's I installed, programmed and fixed tele-conferencing systems, working for a manufacturer. Some systems used thousands of telephone lines and were controlled by pc's. The systems were also extremely complicated and used custom-made parts and dsp.

Even simple little full-duplex speakerphones and boardroom tele-conferencing systems had custom-made parts and a program for their dsp. Defective ones weren't repaired, they were thrown away. ;D