How many simultaneous outbound calls?

I’m using the call file for outbound calls, but i don’t how many calls asterisk can handle at the same time; what factors that has the effect on that number and if i want to increase the number of simultaneous outbound calls, what should i do?

The number of analogue lines, or ISDN channels. The available IP bandwidth for VoIP. The limit imposed by your contract with the service provider.

For some uses, available CPU power may be a factor.