Communications Engineering Services (CES) provides the equipment, support, and expertise necessary to operate the statewide EMS communications systems and to support public safety interoperability in direct alignment with the Vision 2030 key goals of developing, sustaining, and collaborating with relevant constituents for the advancement of EMS communications. CES ensures that every county and every town in Maryland has a well-functioning, up-to-date, and accessible EMS communications and response system through continual evaluation and maintenance. CES overcomes challenges by successfully maintaining strong partnerships and communication with public safety partners, including Maryland State Police, Maryland State Highway Administration, Department of Natural Resources Police and Forestry, Maryland Department of Transportation and the Transportation Authority, Maryland Department of Emergency Management, Homeland Security Border Protection, and our 9-1-1 centers and Counties.
EMRC / SYSCOM
Maryland’s Emergency Medical System’s communications hub is composed of two integrated components, Emergency Medical Resource Center (EMRC) and Systems Communications (SYSCOM). Both the EMRC and SYSCOM function 24 hours a day, 365 days a year.
EMRC manages communications between prehospital emergency medical services clinicians and emergency departments, trauma centers, and specialty centers to facilitate medical consultations. During major medical incidents, the EMRC shares up-to-date situational awareness regarding the activities, capabilities, and capacities of hospitals and the prehospital system. The EMRC provides initial alerting, coordinates resources, and manages patient distribution This year, EMRC handled 216,757 telephone and radio calls. These calls included communications involving administrative/ operational support issues, single patients, incidents with multiple patients, and calls involving online medical direction. With integration of the Emergency Department Advisory System (EDAS) the center monitors and shares hospital status information with 911 centers, EMSOPs, MIEMSS officials and hospitals.
SYSCOM handles requests from EMS, law enforcement, homeland security, and disaster management, and coordinates helicopter resources for medevac and other missions. The Maryland State Police Aviation Command (MSPAC) Operational Control Center is located within SYSCOM, where MSPAC Duty Officers to coordinate missions. SYSCOM coordinated 4,369 total (law enforcement, search-and-rescue, medevac) flight requests, including/resulting in 1,864 patients flown to specialty referral centers.
EMRC Back-up Sites / Continuity of Operations
MIEMSS Continuity of Operations Plan (COOP), developed in FY 2024, evaluated current systems and recognized areas where mission specific needs required attention. MIEMSS identified an essential need for an additional Emergency Medical Resource Center (EMRC) and System Communication (SYSCOM) as a Backup Center capable of fully supporting current EMRC and SYSCOM operations if the primary communications center becomes unusable due to a building infrastructure failure, disaster, or other unplanned event. In 2022, MIEMSS and Harford County Department of Emergency Services began to integrate MIEMSS operations at their 9-1-1 Center. MIEMSS Communication Engineering successfully implemented a new console to fulfill the needs of the COOP plan and install a backup center geo-diverse from MIEMSS. In 2025, This project was able to meet some of the equipment needs through alignment with the Communications Upgrade Project (CUP) project, though more equipment is necessary to ensure full operation of this critical backup center.
Maryland First Responder Interoperable Radio System Team (MFiRST)
Maryland First Responder Interoperable Radio System Team (MFiRST) is a statewide encrypted radio system that provides radio communication across the entire State. The system provides air-to-ground channels for public safety flight operations that directly support the Maryland State Police Aviation Command (MSPAC) medivac operations. By serving on the Radio Control Board and Operations Committee, CES provides oversight of the operation and maintenance of the Statewide Public Safety Interoperability Radio System. This enabled the implementation of an interface that provides Maryland jurisdictions with use of MFiRST for medical consultations and guidance through the EMRC. With the additional implementation of P25 phase II upgrades, Maryland State Police Aviation Command will be able to fully migrate to MFiRST systems.
A primary goal of MFiRST is improving coverage by eliminating communication dead spots. While this goal is being achieved, CES continues to maintain the VHF low-band system for statewide communication, promoting integration of aviation talkgroups (AVTacs) within MFiRST, and establishing a shared communications platform for counties and aviation resources to enhance the continuum of care. Currently, Talbot, Caroline, Carroll, Cecil, Queen Anne’s, Kent, Harford, Allegany, Garrett, Dorchester, Somerset, Washington, Wicomico, and Worcester Counties have implemented AVTacs, with plans to include additional counties as MFiRST completes statewide deployment.
Public Safety Interoperability Network (PSInet)
MIEMSS Communications Engineering Services (CES) deploys, administers, and maintains the Public Safety Interoperability network (PSInet), a statewide, private IP-based public safety network comprised of fiber, microwave, and wireless links that support critical data and voice. Essential to future operations and implemented through the Communications Upgrade Project (CUP), PSInet is the foundation for Maryland’s transition to an IP-Based EMS communication systems. The network provides connectivity into Maryland State Police barracks, MIEMSS regional operating centers, jurisdictional emergency operations centers (EOC), public safety answering points (PSAP), state and jurisdictional health departments, hospitals, and other allied agencies. Applications that currently operate on PSInet and Maryland First Responders Interoperable Radio System Team (MFiRST) include the Digital Emergency Medical Services Telephone (DEMSTEL), Central Maryland Area Radio Communications (CMARC), other systems monitoring/controlling the state’s public safety microwave network, and tower infrastructure.
Communications Systems Maintenance and Improvements
In FY 2025, CES continued to migrate systems to new, more resilient technologies that enhance services provided to the EMS community. The department focused on several major projects to ensure a well-functioning, up-to-date, and accessible EMS communication and response system, including:
- Public Safety Microwave Systems updates • Continued work on the Communications Upgrade Project (CUP) • Addressing issues related to the Verizon copper etirement project
- Maintaining and servicing communications systems on a full schedule
- Leveraging newer communications systems such as MFiRST while maintaining current systems
- Partnering with Anne Arundel County to use its MultiProtocol Label Switching (MPLS) network, enhancing reliability and geo-diversity of PSInet.
CES leads the design, implementation, and maintenance of Maryland’s Microwave System for EMS communications. This critical infrastructure supports MIEMSS, Maryland State Police (MSP), Maryland Department of Natural Resources (DNR) Maryland State Highway Administration (SHA), Maryland counties’ public safety radio systems, and other partner agencies. This system includes the statewide 700 MHz radio system project (MFiRST). Microwave systems are critical for reaching remote areas within that state that do not have access to newer technologies.
FY 2025 highlights within the current communication plan include upgraded microwave links to enhance reliability and resiliency, strategically placing Ethernet-capable radios in locations to further support CUP, upgrade of microwave links across Maryland that provides a more robust and reliable transportation of radio traffic (backhaul) for long-term sustainability of the EMS communication system.
The following significant microwave path replacements and new microwave links that expand the native Ethernet network and enhance connectivity for CUP:
- Allegany 9-1-1 to Allegany COB
- Oxon Hill-District Heights
- District Heights to PGCCF
- District Heights to DC Children’s hospital
- Doctors’ hospital to Cobb
- Ellicott City to Timbers
Since 2019, CES has steadily advanced work on CUP. To decrease the risk of vulnerabilities and outages from older communication systems and reduction of vendor support, the work on the microwave system and PSInet has supported critical upgrades required to advance CUP, and proactive replacement of these systems ensures systems like the Region III patching system that is 28 years old to maintain quality and reliability while working to bring the new systems online, the primary goal of CUP.
CES upgraded the primary and secondary Master Alarm monitoring servers to new Linux servers and continued integrating the MFiRST system alarms into the MIEMSS master alarm system. This integration enlightens system maintenance and performance issues and provides for rapid identification and diagnosis for system improvements while leveraging the state’s investment in the master alarm system to enable an overall comprehensive view of MIEMSS, DNR, SHA, and the MFiRST radio infrastructure. This year, MIEMSS supported the installation of enhanced alarm monitoring systems at additional MIEMSS’ tower sites and hospital locations.
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Access to PSAP via 911
The three digit number 911 is used to access the local Public Safety Answering Point (PSAP) in every jurisdiction within the state. By state law, access to 911 was implemented on July 1, 1985. Additionally, by law, enhanced 911 access was mandated by July 1, 1995. Implementation in Maryland of Wireless 911 that includes Automatic Location Information was somewhat slowed because of waivers that were granted by the FCC to the wireless industry. However, significant progress has been made over the past two years with focused efforts instituted by the State Emergency Numbers Board. Funding to support 911 services is through telephone subscriber fees administered by the State Emergency Numbers Board.
Ambulance and EMS Dispatching and Communications
Each county is responsible for the dispatch of its ambulances, usually in response to a 911 call or request from another emergency services clinician. Ambulance dispatching is accomplished by a variety of means, such as manually or computer aided, and initial control is usually maintained by using a fire channel (VHF, UHF, or 800 MHz). All counties have implemented EMD programs to provide pre-arrival instructions to callers to assist in stabilizing patients prior to the arrival of medical assistance.
Once at the incident scene, the medical clinician can use existing medical protocols or may require medical direction depending on the patient’s condition. The clinician accesses the EMS communications system via a EMRC Call channel, county talkgroup Call Channel or Maryland FiRST Call Channel (in some states defined as a Hailing Channel) to obtain a medical channel for consultation with the hospital emergency department.
There are two types of EMS radio communications systems in use within Maryland: Regional (EMRCs) and local. There are currently four regional centers. The Region III EMRC is operated by MIEMSS and services Baltimore, Anne Arundel, Howard, Harford, Carroll, and Cecil counties and Baltimore City. MIEMSS also operates the Region V EMRC which services Frederick, Montgomery, Prince Georges, Calvert, Charles and St Mary’s counties. The Region 1 EMRC servicing Allegany, Garrett, and Washington Counties is operated by Allegany County in partnership with MIEMSS. The Region IV EMRC servicing eight counties on the Eastern Shore is operated by Talbot County in partnership with MIEMSS.
1. EMS Region III EMRC
The EMS Region III med-channel radio communications system is the most complex system in the state. This necessary complexity is due to the population density and the number of medical resources within the region.
EMS Region III comprises Baltimore City and the five surrounding counties. For communications purposes, however, Cecil County (part of region IV) is included in the region III EMRC. The region III EMRC is located in Baltimore at the MIEMSS building. Med-Channel communications is received at EMRC via one of 24 base station sites or through interfaces with local jurisdiction’s 800 MHz systems. EMRC is the central location for establishing medical consultation within the region. Whenever there is a need for medical consultation, the clinician contacts EMRC on Call 1. The EMRC operator directs the clinician to the appropriate med-channel and establishes a patch to the appropriate medical facility. Consultation facilities and multiple hospitals can be patched into a single consultation. The EMRC can also be accessed by local and 800 service dial telephone and a tie into the Region 3 EMRC provides access to all Region 3 area medical facilities.
A Trauma Line radio system is present at the R A Cowley Shock Trauma Center. RF radiating cables allow communications with the attending trauma physician via a portable radio on Med-Channel 5.5. This provides a means for field clinicians to receive medical consultation on trauma patients without the Shock Trauma physician’s movements being restricted.
The EMRC operator maintains a computerized status of all hospitals in the region. The system is known as CHATS (County Hospital Alert Tracking System). The operator provides notification of changes to a hospital’s status to the affected jurisdictions. The CHATS information is also available via the internet from the MIEMSS website.
2. EMS Region V
Region V is served by the region V EMRC located with the region III EMRC at the MIEMSS building in Baltimore. Operation of the region V EMRC is like that described for Region III. It includes Maryland hospitals located within the region, as well as Washington, D.C. hospitals and Frederick County. The region V EMRC is accessed via Med-Channel Call 2 as well as county talkgroups. With the advent of the Maryland FiRST radio system, talkgroups have been setup in to provide the Call and Med interfaces for FiRST users. A tie into the Region 3 EMRC provides access to all of the Region 3 area medical facilities.
3. EMS Region IV (upper shore)
The Eastern Shore area of Maryland’s EMS Region IV (Caroline, Dorchester, Queen Anne’s, Talbot, Wicomico, Worcester, and Somerset counties) are served by a regional EMRC located in Easton. The operation is provided by Talbot County using equipment provided and supported by MIEMSS. Access is via Med-Channel Call 2. Several counties also utilize an interface with their 700/800 MHz radio systems for EMS communications via the EMRC. With the advent of the Maryland FiRST radio system, talkgroups have been setup in to provide the Call and Med interfaces for FiRST users. A tie line to the region III EMRC provides access to Baltimore and Washington area medical facilities.
4. EMS Region I
Region 1 (Allegany, Garrett, and Washington counties) is serviced by the EMRC operated by Allegany County in partnership with MIEMSS, located in Cumberland. Access is via Med-Channel Call 1. With the advent of the Maryland FiRST radio system, talkgroups have been setup in to provide the Call and Med interfaces for FiRST users. A tie line to the region V EMRC provides access to Baltimore and Washington area medical facilities.
Existing Med-Channel Sites
There are presently over 95 med-channel base station sites within the state. The present system allows approximately 95% radio coverage 95% of the time. Voters are used for automated med channel site selection by the EMRCs.
Med-Evac Helicopter Communications System
1. SYSCOM Helicopter Communications
By regulation, MIEMSS is responsible for med-evac helicopter communications. All med-evac helicopters transporting patients to or from medical facilities within Maryland are required to communicate with SYSCOM. For this reason, twelve VHF 44.74 MHz, six 700 MHz helicopter communications sites were installed across the state and a talkgroups were established on the Maryland FiRST trunked radio system. These sites were strategically located to ensure radio coverage to and from helicopters as reliably available over approximately 95% of the state. The 44.74 MHz communications system uses a voter and transmitter steering device to select the correct site.
The Maryland State Police (MSP) Aviation duty officer, stationed in SYSCOM, has primary responsibility for the dispatching of MSP helicopters. In addition to MSP, U.S. Park Police helicopters may be utilized for med-evac operations. MIEMSS is working with commercial air ambulance services in Maryland to provide use of those services in the event that the MSP helicopters are unavailable or significantly delayed.
Medical communications from the helicopter to trauma centers and other medical facilities are provided by the Region III and Region V EMRCs located at MIEMSS using 47.66 MHz base stations at 10 locations throughout the state. Maryland FiRST also established a six-site 700 MHz multicast system and Maryland FiRST trunked talkgroups for medical patching. Using the EMRC patching systems, the helicopter medic can obtain medical direction or give reports on patient condition to any medical facility in the state.
2. Flight Following System
A flight following system in SYSCOM provides visual awareness of the status and location of all MSP helicopters. The system utilizes the FAA’s newest tracking system known as Automatic Dependant Surveillance-Broadcast (ADS-B). MIEMSS has partnered with the FAA to increase the coverage area of ADS-B by utilizing the state’s tower sites and transport systems.
The system allows the MSP duty officer to locate and dispatch the nearest helicopter to the scene of an incident. In addition, the system provides an alarm feature which identifies helicopters that are out of communications with the system which allows helicopter emergencies to be quickly identified. Graphic and text displays can be used to locate emergencies, enabling fast responses when a helicopter may be down or in trouble.
3. Statewide Infrastructure Project
Starting in early 2000, MIEMSS as a key participant in Maryland’s statewide project to construct the necessary infrastructure to support a public safety 700 MHz communications network began upgrading the old analog microwave system with new digital equipment.
The new microwave system is based on 28 T-1 point-to-point links between all of the usable existing and newly constructed communications towers. Connectivity to the county 9-1-1 Public Safety Answering Point (PSAP) centers is included. The system is divided into five separate backbone segments, northern, western, southern, eastern, and the Baltimore City hospital segment.
MIEMSS has provided all of the engineering services for the design of this network. Other allied State agencies have contributed to the installation of the equipment. Towers and microwave equipment are provided by both the State and the local Counties in a partnership arrangement. Monitoring of the network is primarily done by MIEMSS with access to the management system available to the county and state maintenance personnel.
Updated 10-1-2025