Asterisk plus firewall on same workstation

We are trying to save money on our electrical cost and want to run both asterisk and ipcop or monowall on the same work station. I would like your opinions on this. I am just a little concerned about security. We have been using asterisk and ipcop for a long time but this time, we just want cut back on its power consumption. If possible, may need newer hardware if we want this system to go into sleep mode from 11 pm to 6 am.



Keep the phone system separate.
Although it is possible, doing so is asking for trouble.

The cost of troubleshooting an incident when feature stops working will be greater than the $300 it costs to keep an extra server running.