Make a call from the command line

I’m using Asterisk 1.2 on a debian and have a few snom 300/320 SIP phones.

Is it possible to create a call from the Asterisk command line for a given extension to an outgoing line?

your best bet would be a .call file. Drop it into /var/spool/asterisk/outgoing, set it to call the IP phone as the destination, and then drop the call into an outgoing context, priority 1, exten being the destination #.
It will match patterns. So if you have

[outgoing]
exten => _NXXNXXXXXX,1,Dial(SIP/provider/${EXTEN})

you can drop the call into outgoing,2223334444,1.

check voip-info.org for more info on .call files…