We are working on a "learn-as-you-go" project and we are running into a roadblock. I was hoping to get some clarification on a point.
We have 2 NEC Aspire PBX systems. They exist in seperate buildings and are currently connected via a point-to-point t1 circuit via a kentronix conditioner. We have an IP Network running between the buildings. So, our idea is to connect the PBXs to cisco routers (via t1 controllers). One router would convert the voice traffic to voip, pass it through the ip network, and the other router would pass it back. The idea is that the routers would simulate the t1, the PBXs wouldn't be the wiser, and we would save hundreds of dollars a month.
However, I need to get DSP cards for our routers to convert the voice to data. I can get 8,16, 32, and 64 channel DSPs. Based on call volume, I don't believe I need more than 16 channels and I may not need more than 8. So, let's say I go with the 16 channel DSP. However, I am worried that, becuase the PBX is connected to a T1, it's going go assume that it can use 23 channels and may use the 17th channel, even when there aren't 16 concurrent calls. And, that call would be dropped.
So, my questions are...
1. What is the behavior of the PBX? Would it always use the lowest available channel or would it use higher channels, even if the lower channels aren't in use?
If you can't speak to the NEC product, can you speak to PBX systems & t1 technologies in general?
2. Is this even a concern? Maybe I am overstating the necessity of having the channels "line up". Maybe when the PBX uses channel 17, the router is still going to connect it, as long as the concurrent calls don't exceed 16.
Any other comments or suggestions would be appreciated.