How do you make a phone call with an extension line?

Question

How do you make a phone call with an extension line?

Answer 1

dial the number to the office you are calling..

when the automated voice comes on enter the extension number, if you are unable to dial the extension number directly dial 0 after being connected to the automated system, and ask to be connected to the extension

Answer 2

is this for an office? if it is you will need a PBX. this will let you call from phone to phone with out going out on an outside line.