Is there any way(card/hardware) to increase the number of channels of an asterisk server? Or just performance & tuning?
William
What exactly are you refering to when you talk about channels?
DicksonC,
I meant phone user’s connections.
The number of call appearances is a function of the phone’s capabilities, not asterisk.
Let me rewrite this question:
if my box at maximum can connect 200 users simultaneously. is there any telephony hardware to put in it that I could possibly handle more users?
Just a thought
William
You are asking for a solid answer to a slippery question 
There are many things that will constrain how many calls a server can take. Assuming we’re talking solely about server capacity, and not capacity limits created by a particular configuration…
The biggest thing that will slow down a server by far is transcoding. If your server is converting from one codec to another, that is your limitation. This can be fixed by not transcoding or alternatively add more CPU power.
another big thing that will load up a server is dealing with media (voice data). If the phone is sending the voice data to the server and the server sends it back to the other phone, the server has to handle every byte of voice data. It will do this if you do canreinvite=no. Try to use reinvites if you can, use nat= and other such things instead unless absolutely necessary. Not placing * behind nat can help alot with this. Not passing media through your server can give you another 100-200 channels worth of capacity. However, this can be offset by upgrading your server’s network interface to gigabit or something based on PCI-X or pci-express.
Lastly, one thing you might consider is using * in conjunction with SER or siproxy. That will take at least some of the load off Asterisk, or allow you to load-balance between multiple * boxes.