FM Emergency Message Break-in System - Optical Master Units (OMUs)

HELIOS® FM Digital Optical Transport System with emergency message break-in system and broadcast monitoring support is designed to extend the coverage of Public Safety Radio into large Public Venues, such as long Tunnels sections and large mines, underground parking lots, highway, railway and etc.

Utilizing a centralized digital CPRI distributed architecture, HELIOS® FM Digital Optical Transport System is a two-tier architecture consisting of the Optical Master Units (OMUs) and Optical Remote Units (ORUs). RF signals from Base Stations, off-air, can be received. The signal is filtered and then converted to a digital CPRI data stream. The digital CPRI packet data stream is transported via single mode fiber and received by the ORUs. The ORUs then convert the digital CPRI packet data stream back to RF and amplify the signal for delivery to the antennas, or radiating cable.

 The whole system network topologies including star, chain and hybrid to cater to different deployment scenarios. These network topologies provide reduced fiber plant usage and installation cost, and effective fiber loop redundancy configurations.

Manual or automatic delay calibrate support

Enable to manually or automatically adjust the delay value in different ORU to eliminate the delay dispersion interference in the overlapping area of signal coverage between adjacent ORU’s.

Emergency message break-in

Option to insert standard AES3 emergency messages to all the OMU channels.

Broadcast monitoring

Supports FM broadcast monitoring and selectable in each OMU channels by software.

Independent AGC

Enable to automatically adjust the Gain of each OMU channel to balance the output of each channel in the ORU’s


Enable to detect downlink activity and support muting. This means that when there is no activity in the Downlink, the Downlink is automatically closed in FPGA. When service is made, the Squelch Algorithm activates the Repeater Downlink Channel.

  • ALL Digital Software and Hardware Platform
  • CPRI Transport between OMU’s and ORU’s
  • Supports 4 Digital Optical Output Ports for each OMU
  • Supports up to 8 Remote Units cascading in each optical port
  • One OMU support up to 32 Remote Units connection
  • Single Fiber core to transport
  • Supports up to 10 Gb/s Digital Optical Fiber Speed
  • Option Embedded 6.35mm headset port for FM broadcast monitor
  • Loop redundancy support
  • Optional embedded emergency message break-in system
  • Long transport distance and accurate delay calibration
  • RF composite DL output power +37dBm, +40dBm and +43dBm option
  • IP67 and wall mount or pole mount of ORU
  • 19” standard Rack case design of OMU
  • RJ-45 Port in OMU to support Local Control and Alarming via software
  • Additional RJ-45 Port for external ethernet and wireless modem
  • SNMP V3 and MIB File

Electrical Specification

Frequency Bands: 87.5-108MHz

Number of Filter: Up to 16 @downlink

Filter Bandwidth: 200KHz

Operation Mode: FM Broadcast and emergency message Break-In

Transport Protocol: CPRI

Distance: 20 Km (Based upon SFP module)

Number of Digital Optical Ports: Up to 4 optical ports and support 16 remote units with loop redundancy

Optical Bypass: Optional for non-loop redundancy architecture

Squelch: Downlink Squelch support

Master Unit Alarm Detection: PSU alarm, Optical Transceiver alarm and etc.

SNMP: SNMP V3 + MIB file

Power Supply: 220V AC 50~60Hz

External and Antenna Connection

Local Alarm Indications: LED alarm display

Local Control: RJ-45

Remote Control: Additional RJ-45 port to connect external modem or Ethernet

RF Connector: 1* N-Type Female

Optical Connector: 4 * LC/UPC

Mechanical Specification

IP Rating: IP30

Temperature Range: -25℃ to +55℃

Dimension: 19” 2U

Weight: Max 8kg