STEP : 1
Open Developer Console of Zoho Account : https://accounts.zoho.com/developerconsole
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 :
http://server_ip/techextension/AsteriskSupport/soap.php?phone=123123123
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.