How to Asterisk configure

asterisk , SER, OpenSer are open Source VoIP Servers.
Aserisk: You can configure the VoIP server using by Asterisk. The installation & configuration instructions are given below...

1. Download the asterisk form asterisk .
2. Install using make ; make install command.
3. Configure the sip user in sip.conf file and write the dialing extension in extensions.conf
sip User format
[user name]
type=
host= dynamic
context =
secret =
disallow= ; codes configuration
allow= ; codes configuration
............etc
and extension as
[context name]
dial => X,1,Dial(SIP/${EXTEN}@call termination context name |call dialing time duration like '30')

Anand Dayal
akdayal@yahoo.com