How can i block STD and ISD calls and other problems on E1

Asterisk Asterisk Support
1

Hi
I am using ASterisk and a PRI connection having 30 channels with E1 card and from India. I am facing three problems

  1. I am unable to block STD and ISD calls on all the phones and particular phones. How to write the dial plan?

  2. My dial plan is 6|. which i make calls with prefix 6 and then the number. I am not able to make calls to BSNL(provider). Why i am not able to make calls to particular provider?

  3. I want to make a phone always dedicated to particular channel or trunk. Which always will be open to that phone only. How can i do this?