The Ohio Multi-Agency Radio Communications System (MARCS) is a state-wide trunked radio system serving state and local agencies.  Its primary state users are the Ohio State Highway Patrol, Ohio Homeland Security, State Fire Marshall, Department of Natural Resources, Emergency Management Agency, Department of Health, Department of Rehabilitation Services, and Department of Youth Services.  You can learn more about MARCS by visiting their website. In 2014, Ohio replaced the MARCS system with a new P25 system called MARCSIP – and Butler County connected the BRICS system to it. Numerous local systems are now also connected, and many local governments in Ohio use MARCS infrastructure as their system.

Ohio MARCS interoperability talkgroups have been provided in zones M0 through M9.  They may only be used in an emergency or as directed by a dispatcher.

MARCS has divided the state into four areas.  Butler County in zone 3 (zone as in geographic area, not zone in your radio template). This relates to which MCALL and MCOMM talkgroup is most appropriate. Learn more below.


Click to view full size of MARCS IP Interop talkgroups

Talkgroups – What are they all for?

SWMATAC (or MA TAC) 1-28 Southwest Ohio Mutual Aid Tactical Talkgroups

These talkgroups can be used for incident / event interoperability in southwest Ohio. MA TAC 11 and 12 are earmarked for incidents in Butler County. They can be assigned by any Butler County dispatch center.

LECOMM 1-8 Local Emergency Communications

These are generic “event/emergency” talk groups for MARCS non-state agency users.  LECOMM offers the ability to talk to any other non-state user when involved in an planned event or emergency.

These talkgroups are NOT monitored by MARCS. (Prior to using, caller must announce intent to use and determine if objections exist. These LECOMM talkgroups are specifically for “local” event/emergency situations, and are only imbedded in non-state agency equipment.)

ECOMM 7-28 Emergency Communications

These are generic “emergency” talk groups for MARCS users. To be used to talk to any other user when involved in a MARCS-coordinated emergency. At a multi-agency scene, Command / Communications / Control would steer responders to these talkgroups, based on functional work groups. (E.g. A MARCS-equipped CCC would direct “All incoming traffic units go to ECOMM 9”,  “all incoming rescue units go to ECOMM 11”,  “all incoming hot zone units go to ECOMM12”, etc.)

E-COMM 7-19 will be coordinated (requested) through the ODNR Columbus comm center.

ECOMM 20 is designated as the statewide emergency talkgroup, for use by the state executive branch to disseminate announcements to other agencies during a disaster. ECOMM 21-28 are utilized for Homeland Security Regions 1-8 (HS Region 1 – use ECOMM21).


This talkgroup is constantly monitored by the Ohio Office of Information Technology/MARCS-dedicated helpdesk, located at the State of Ohio Computer Center in Columbus.

The Helpdesk’s primary purpose is to assist MARCS equipment users with problems encountered with the MARCS voice or data systems statewide. It can also be used as the initial point of contact for MARCS command staff.

The helpdesk may also be reached 24/7 @ 1-866-OH-MARCS (1-866-646-2727).

MARCS 1-14

These are talkgroups established for additional interoperability between MARCS users.  They may be used for state or local emergency coordination if desired.


See “Calling Channel” below.


MARCS users generic talkgroups for any user to be able to talk to any other user. These talkgroups are NOT monitored by MARCS base locations.

Generally, a dispatcher would direct you to “go to MCOMM 1 to talk to Officer A,” etc. (While each MCOMM has statewide capability, the theoretical purpose is for “direct” communications in each geographic Zone.)

SCALL and SCOMM 7-12

Generic “emergency” talk groups for communication using one of the MARCS Tower on Wheels (TOWs). To be used to talk to any other user only when the TOW is deployed. As with the ECOMMs, units would be “steered” to these talkgroups; in this case, by MARCS / BRICS personnel or a dispatcher.

SO Talkgroups

See “Sheriff’s Office Talkgroups” below.

Calling Channel

Zones for MCALL and MCOMM talkgroups (click to enlarge)

Zones for MCALL and MCOMM talkgroups (click to enlarge)

The MCALL talkgroups allow users to communicate directly with any Ohio State Highway Patrol post within your geographic zone.  It is also monitored by the Department of Natural Resources communications center in Columbus.

We would use MCALL-3 located in Zone M4, channel 5 in your radio.

If you use this talkgroup, remember that all counties and posts within this geographic zone can hear your transmission.

This talkgroup is the prefered way to reach the ODNR Communications Center and the OSP Communications Center in Columbus.

The ODNR center coordinates the assignment of the ECOMM mutual aid talkgroups.  They can be requested via MCALL 3.

Sheriff’s Office Talkgroups

All 88 counties have a MARCS radio installed in their Sheriff’s Office communications center.  The talkgroups are organized by county number.  If you have left our county and need to reach a nearby county in an emergency, you may use these SO talkgroups.

According to MARCS:

These radios are placed in the communication center of the sheriff’s choice. By calling the alpha-based two digit county number (e.g. “GPD Car 321 to SO 59”), you will be communicating with the Sheriff’s Communication Center. Also, the OSHP post in a county monitors that county’s SO talkgroup and those SO talkgroups of adjacent counties.

The regional talkgroups correspond with the geographic regions established by BSSA and MARCS during the planning for the MARCS radio installations at each SO. They follow established ODNR boundaries. Calling on an SO regional talkgroup will result in all SO’s within that region being hailed. ODNR’s central dispatch center in Columbus also monitors these talkgroups.

Regions for SO talkgroups (click to enlarge)

Regions for SO talkgroups (click to enlarge)

Due to space constraints in the template, BRICS radios contain (in Zone M8) the regional SO talkgroups and the following individual county talkgroups:

OH SO-1, Adams County
OH SO-8, Brown County
OH SO-9, Butler County
OH SO-13, Clermont County
OH SO-14, Clinton County
OH SO-29, Greene County
OH SO-31, Hamilton County
OH SO-34, Highland County
OH SO-57, Montgomery County
OH SO-68, Preble County
OH SO-83, Warren County

Our Centers and Radios

Every communications center using BRICS is equipped with the SO-09 talkgroup on their radio consoles. With this talkgroup, a user on the MARCS system can hail any communications center in Butler County. It can also be used to hail the dispatcher for the highway patrol’s Post 9. This talkgroup is to be used for hailing and information broadcasts only; never an ongoing incident or event.

BRICS consoles are also equipped with the MCALL-3 talkgroup, allowing them to reach ODNR Columbus and OSHP Columbus by radio.

In addition, dispatchers are equipped with law enforcement and fire portables with the same full MARCS suite as in the field, allowing them to monitor other talkgroups if needed.

Emergency Use Only

Agencies outside of Butler County that use MARCS as their primary means of communication pay a monthly fee. We are able to uses MARCS interoperability talkgroups in our template for free, on an emergency basis, due to our interconnection between BRICS and MARCS. MARCS has an agreement with Butler County, as a whole, to allow this. Be mindful that your use of MARCS interoperability talkgroups is subject to their policies and misuse could affect all Butler County agencies, not just your own.

MARCS interoperability talkgroups are available for any emergency or situation requiring interoperability with other MARCS users. Please contact the BRICS office with any questions about how to use these talkgroups or work with their users.

Examples of MARCS Use

Working with ODNR

Oxford Township PD is on a call near Hueston Woods State Park and needs to have information passed along to the park ranger. Oxford Communications can reach the ODNR Columbus center using MCALL-3. ODNR calls the Hueston Woods ranger on their local talkgroup and asks them to hail Oxford Communications on SO-09 for the information.

Sharing Information with State Law Enforcement

A bank robbery has occurred in Hamilton and the suspect was last seen heading north on SR-177. Butler County Communications makes an All-County Broadcast (ACB) to alert neighboring agencies. In addition to alerting Oxford and BCSO, the ACB includes SO-09. As a result, the highway patrol and ODNR officers at Hueston Woods receive the suspect information.

Responses outside Butler County

The Ohio EMA has requested the Butler County Technical Rescue team respond to a structural collapse in Dayton. The EMA established an ECOMM talkgroup for the incident by requesting its assignment through the ODNR Columbus center. The Technical Rescue team can monitor the incident as they travel to the scene and immediately establish communication with the command post in Dayton.