STEP : 1 
Open Developer Console of Zoho Account :

STEP 2 :

a ) Click on Add Client ID button.

b ) Put Below Details on form as below :

Client Name : TE CRM Asterisk Integration

Client Domain : localhost

Authorized redirect URIs : http://localhost/zoho/abc.php

Client Type  :  WEB Based

STEP 3 : You will get Client id and Client Secret as below

STEP 4 : Paste Client ID and Client Secret in crmconfig.php file under techextension/AsteriskSupport  as Below : 

STEP 5 : Now Generate value for code as below :

a ) Click on Vertical 3 dots
b ) Click on Self Client

STEP 6 : Enter Below Details
Scope : ZohoCRM.modules.all
Expiry : 10 Mins
and then click on View Code button

 STEP 7 : You will get Code as below copy that code and paste it under crmconfig.php file

STEP 8 : Run soap.php file with phone parameter in browser which generated Grant Token in Techextension Module

The link to call soap.php is as below : 

phone (123123123 ) is just sample number you can use any number.

You are done with Generating Token, now you can use Techextension Zoho Asterisk Integration with latest Zoho API v2.