1]Insert other than one Rs coin and check what 
happens.eg.Insert 50 paise coin and check what happens.
2]Insert a valid 1 Rs. coin and check what happens.
3]Insert 1 Rs.coin when coin box is full and check what 
happens.
4]Insert Invalid coin when coin box is full.
5]Insert vaild coin into box with keeping the reciver.
6]Insert the notes(Eg:Rs 10,20) into the coin box and check 
what happens.
7]Insert a vaild coin into coin box when it is not reached.
8]Insert a invalid coin when u want to continew ur talk.
9]Insert a valid coin when u want to continew ur talk.
10]Check for all coin box number buttons are properly 
working or not.

Prerequisite:Phone is attached to a working Tele line.

1.Lift the handset n check for tone
2.Lift the handset n check for "Insert coin message"
3.Insert 1 Re coin n check for "Dail" message.
4.Insert other than 1 Re coin and check what happens.
5.Insert 1 Re coin n dail a valid number
6.Insert 1 Re coin n dail an invalid number
7.Insert 1 Re coin n wait for along time without dialing
8.Insert 1 Re coin n keep the hand set
9.Insert more than 1 coin n dial the number
10.Insert 1 Re coin n check the time got displayed
11.Insert 1 Re coin n check whether time getting reduced by 
1sec or not.
12.Insert 1 Re coin n check whether its prompting the user 
when time limit about to get over
13.Insert 1 Re coin before it prompts the user
14.Insert 1 Re coin when it prompts the user
15.Insert duplicate 1 Re coin 
16.Check Redial option