Understood SIP and IP Telephony in 3 days: For the beginner Paperback – August 13, 2017

Not what I expected. There are much clearer SIP tutorials on the web that what is in this book.

I gave this book to my brother and he was very interested. He has built up an internal communication system between some members of the household. Thanks the author.

weak book many typos

I'm not really sure if the author actually speaks English.