[Asterisk-Users] four wildcards in a single pc

[Peter Svensson]

On Thu, 9 Dec 2004, Steven Critchfield wrote:

> Digium cards need 1000 interupts per card per second due to the lack of
> onboard buffer. The buffer was left off of the design to keep the design
> simple and therefore inexpensive. All the cards present 8 bits of data
> per channel during that interupt and as all telephony is 8000 bits per
> channel per second.... 8000/8 = 1000 service needs per second. An
> interupt is the way hardware requests service. 

A channel is 64000 bits per second or 8000 8-bit samples. The Digium cards 
transfer 8 samples or 64 bits per interrupt per channel. 

Another important reason for the small buffer is to minimize the latency
of a call switched through Asterisk. Larger buffers would imply larger 
latnecies and latency is the enemy of voice communication for several 
reasons that are listed in the wiki.

Peter