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Site Trunking 101


SITE TRUNKING is a safeguard operating mode common  to trunked, multi-site radio system such as the IPSC Statewide 800 MHz system.  Users of conventional public safety radio systems will be unfamiliar with this term and may find the concept difficult to understand.  To begin with, it is important to understand that SITE TRUNKING DOES NOT MEAN THE SYSTEM IS DOWN! It is critical for users to train to recognize and appropriately respond to site trunking events.

All sites on the statewide system are connected by T-1 telephone lines.  When sites are operating normally via T-1 lines, they are operating in a condition know as Wide Area configuration.  Wide Area allows users to communicate with users that are both affiliated with the same site as the user and those that are affiliated with sites other than the one where a particular user is affiliated.  Hence, users can communicate across cities, counties and even across the State.

However, when T-1 connectivity is broken, the particular site is no longer able to communicate with the system and the other sites on the system.  This condition is known as Site Trunking. The site is still up and operational, but not in "wide area" mode.

Read on to find out more about Site Trunking:

Prepare for Site Trunking!

Even though you may not have experienced a Site Trunking scenario yet, we can almost guarantee that you will.  So, let’s plan for it together!  We remain available to assist further in helping you understand Site Trunking, develop a plan and train your users. Contact Mike Watkins,, for training or for help developing a site trunking plan.

We also have the ability to remotely place a site into Site Trunking for a given period of time.  If feasible to you, this could prove to be a valuable test of your equipment configuration, your communications plan or your training.

Network Operations Center

When a site goes into Site Trunking, a series of reporting and corrective actions automatically begins.  You do not need to contact IPSC. If however, you feel the need to contact the IPSC Network Operations center personnel, you may do so by calling 317-234-1540 from 0700 – 1800 Monday through Friday. PLEASE LEAVE A MESSAGE or dial the pager personnel be paged after hours.  The NOC can be contacted at