How to increase register in a Asterisk-BSD system

I’m a newbie using Asterisk. After deployed Asterisk-BSD system on CentOS, the system support only more than 100 register. Now, i want to increase the the register up to 1000 with Asterisk. Please help me.

Centos == Linux

FreeBSD == BSD

Orangecake, i think you have some mistake, this is a BSD area not Linux.

See you!!!