Method for avoiding call blocking

摘要

Methods for avoiding a call blocking feature. In a first method a list is kept for the trunks previously used to call a particular telephone number. Each time that particular telephone number is called a different trunk, not on that list, is used to place the call. The list is cleared and restarted whenever all the trunks have been used. In a second method a list is kept for trunks for which a call blocking message has been received when an attempt was made to call that telephone number. Each time that particular telephone number is called a trunk which is not on that list is used to place the call. Only non-blocked trunks are used to call a telephone number.