Effective 0800 on Monday, September 21, 2015, we will make a permissions modification to the 800 radio network to help EMS agencies comply with the use of an assigned TAC when responding and on scene of calls. Effective 9/21, the requirement to seek permission for use of TAC3 is lifted AND all EMS unit to unit transmissions are to be conducted on TAC3. Previously, many agencies (particularly larger services) used EMS2 for system status management (SSM) and other unit to unit transmissions – those are now transferred to TAC3. As TAC3 is and will remain the TAC assigned to all EMS calls, agencies using TAC3 for SSM will already be on the assigned TAC. The only exception to our assignment of TAC3 will be when adding EMS to a fire incident. In those cases, it will be necessary for responding EMS units to switch to the TAC assigned to that incident (based on the geographic location and radio traffic at the time of call). There are no other changes in the February 18th policy regarding EMS switching to their assigned TAC: all updates on EMS calls will be provided exclusively on the assigned TAC. After calling enroute on EMS1, all units should switch to the assigned TAC and remain on the TAC until leaving the scene. The only exception is needing to reach EMS Dispatch, in which case, it is necessary to return to EMS1 (i.e., arrival on scene, departing for a hospital, clearing a scene in service, etc). Any communications between EMS units on scene or responding and/or fire units on scene or responding should occur on the assigned TAC. If EMS Dispatch is looking for units responding or on scene, they will switch to the assigned TAC to make contact. Once enroute and while on scene, it is not necessary to monitor EMS1 unless your agency policy dictates otherwise.