Skip to main menu Skip to main content Skip to footer


The HelixNets HMS-4X main station is a combination of a system host and an intercom user station with XLR Powerline connections to user stations. HMS-4X hosts up to three HLI interface modules for external connectivity including Ethernet and Fiber. The HelixNet IP networking guide provides specifications, best practices and guidance for the integration of HelixNet into an existing or new IP network.


HelixNet System Operation

  • HelixNet 12/24 Channel System Host
  • 6 HMS(2) can link over LAN & WAN
  • Supports up to 64 endpoints on HelixNet system
  • 12 partyline channels; expandable to 24 channels via optional license

Main Station

  • Easy to use CCM™ browser configuration
  • Fast front panel control & configuration
  • Plug-and-go with auto discovery
  • Central upgrades from main station
  • 4 Keysets assignable to channels
  • All Talk, Stage Announce, RMK & Program Audio level controls


  • 2 Powerlines for distribution of Ethernet to HelixNet user stations via XLR cables
  • 3 Expansion slots for HLI modules: Ethernet, fiber, 2-wire & 4-wire ports
  • Program Audio input
  • Stage Announce output
  • 4 Contact closure inputs & outputs

LQ Integration Options

  • LQ® linking for high density 2-wire, 4-wire and GPIO expansion
  • Station-IC™ and Agent-IC® as integrated via optional licenses
  • SIP/VoIP integrated via optionally licensed LQ

Item Code

HMS-4X HMS-24-UG: 24-channel license

Optional Interface Modules and SFPs (Sold Separately):

HLI-2W2: 2-wire module

HLI-4W2: 4-wire module

HLI-ET2: Ethernet module

HLI-FBS: Fiber module

HLI-MMFO: Single-mode SFP

HLI-SMFO: Multi-mode SFP



HMS is required as the HelixNet Host. Link Group may include five additional HMS members, including up to three LQ devices for a maximum of six HMS/LQ in Link Group. HMS link using HLI-ET2 or HLI-FBS modules over LAN/WAN connections. Link Group supports up to 64 endpoints (station/port).

Note: HMS does not link to Arcadia.


System provides 12 or 24 intercom channels assignable to any user station or port in the system. Four Channels can be assigned to station. Program Audio can be associated with any channel with independent endpoint level control.


99 Roles for naming and dynamic configuration of user station settings. Role can be applied to multiple user stations.


Host: HMS-4X

Activation: Generated to unique HMS-4X device System ID

Transferable: No, fixed to HMS-4X

Recovery: Yes, by Clear-Com Support or Service Center

Permanent Licenses

Part numbers: HMS-24-UG

Capability: 24 Channels

Validity: Perpetuity


XLR Powerline: (2) 3-pin XLR-M/F

Gooseneck Mic: 3-pin Tuchel

Headset: 4-pin XLR–M

Program Audio: 3-pin XLR–F

Stage Announce: 3-pin XLR–M

Hot Mic/IFB Interface: 1/4\" (6.35 mm) TRS Jack

GPIO: 25-pin D-type female (4 GPI, 4 GPO, 5V)

USB: Type A & Micro AB (factory service use)

Input Power Connector: IEC-C14

Microphone Pre-amplifier

Headset Mic Impedance: 200O (Dynamic)

Headset Mic Voltage: 1.7V (Electret selectable)

Limiter: +23dB

Route to 4-wire output at 0dBu: Mic Gain: 60dB (Dynamic), 45dB (Electret)

Frequency Response: 200Hz – 10 kHz ±3dB

Distortion: <0.2% THD @ 1kHz

Noise: <-55dBu (Dynamic), <-65dBu (Electret)

Headphone Amplifier

Load Impedance: >32O

Output Level: +12dBu before clipping

Sidetone: -12dB (selectable)

Route from a 4-wire input at 0dBu: Max Gain: 0dB

Frequency Response: 40Hz - 10kHz ±3dB

Distortion: <0.1% THD @ 1kHz

Noise: <-65dBu

Headphone Limiter: 0dB (selectable)

Loudspeaker Amplifier

Load Impedance: 8O

Output Level: +18dBu before clipping

Route from a 4-wire input at 0dBu: Max Gain: 18dB

Frequency Response: 200Hz - 10kHz ±3dB

Distortion: <0.1% THD @ 1kHz

Noise: <-50dBu

Program Audio Line Input

Maximum Level Before Clipping: +18dBu

Nominal Input Level: 0dBu (selectable)

Input Impedance: >= 10KO

Route to 4-wire output at 0dBu: Frequency Response: 20Hz - 10kHz ±3dB

Distortion: <0.2% THD @ 1kHz

Noise: <-65dBu

Stage Announce Output

Maximum Level Before Clipping: +18dBu

Nominal Output Level: 0dBu (selectable)

Output Impedance: <= 100O

Route from a dynamic headset: Frequency Response: 300Hz - 12kHz ±3dB

Distortion: <0.1% THD @ 1kHz

Noise: <-55dBu

Hot Mic Output

Maximum Level Before Clipping: +12dBu

Nominal Output Level: 0dBu (selectable)

Output Impedance: <= 100O

Route from a dynamic headset: Frequency Response: 300Hz - 12kHz ±3dB

Distortion: <0.2% THD @ 1kHz

Noise: <-55dBu


Two independent network XLR Powerlines Frequency Modulated Ethernet - OFDM

Output Voltage: ±29.5V DC

Output Current (Max): 1.5A per Powerline

Frequency: 100kHz-25MHz Requires shielding integrity between Powerlines

Support up to 10 beltpacks each

Support up to 3-10 stations each

Use HelixNet Cable Calculator to validate load and cable distance.

Logic Power Output

To power Logic Inputs

Output Voltage: 5V, separate pin

Current (Max): 1mA

Logic Inputs -GPI

Assignable to talk, call, mic and headset keys

Input: 4

Style: Optically isolated

Detection Voltage (Min): 3V

Input Voltage (Max): 5V

Logic Outputs – GPO/Relay

Assignable to talk, call, SA keys and channel events

Outputs: 4

Style: Power Relay

Normalized: Open or Closed, separate pins

Switching Voltage (Max): 30V

Switching Current (Max): 2A


Input Frequency Range: 100 - 240V AC

Input Frequency Range: 50 - 60Hz

Power (Max): 250W

Input Power Connector: IEC-C14

Practical Power Range: Power (Normal): 80-250W

BTU (Normal): 275-850BTU/hr Dependent on hosted modules and powerline connected beltpacks


32º - +104ºF (0 - +40ºC) 90% relative humidity


1.75 x 19 x 13in (HxWxD)

(44 x 483 x 320mm)


5.83lbs (2.65kg)

Network Specifications (Firmware Version 4.2+)
Network Protocols

Ethernet IPv4–Unicast Audio and Control

mDNS–Multicast Device Discovery

Layer 3 routable with mDNS function limitations


TFTP-File Transport Protocol

NTP–Network Time Protocol

RTP–Audio Transport

WavPack–Audio Codec

Network Ports


Port 69 UDP–Firmware File Server

Port 80 TCP–Web Interface, System Management, Expansion

Port 123 UDP–Time Stamps for Service Logs

Port 655 TCP–Link Group Audio/Database

Port 6001 TCP–System Management

Port 6001 UDP–Audio Streams


Port 5353 UDP–mDNS, Names, Discovery, Linking, Expansion Optional for device names and linking

Mandatory for HMS/HRM Expansion

Network Parameters

Link Group Endpoint Support: 64 Endpoints are user stations, active Interface ports, Program Audio inputs and LQ accounts.

Bandwidth: 300 kbps each audio input linking between HMS/LQ Link Group audio sent dynamically between members 300-600 (max) kbps from each endpoint audio input to HMS 1200-2400 (max) kbps from HMS to each endpoint audio output

Network Jitter Tolerance: <= 128ms jitter buffer per audio stream receiver automatically adjusted to network performance

QoS Tags: DSCP=41, Assured Forwarding (AF)

Link-Local Default IP Address Range:

System Reserved IP Ranges: for endpoints for Link Group

Recommended Ethernet Switches

• Managed Ethernet Switch – Layer 3

• 100/1000 Base-T ports for endpoints

• 1000 Base IP Trunks between switches

• QoS Configuration

• Energy Efficient Ethernet bypass option

• IGMP Snooping bypass option


Please refer to the Clear-Com HelixNet Network Guide for additional switch settings and network characteristics

Ready to get

Our team of communications professionals are here to support your project. Contact us today to start designing your custom intercom solution.

Sales Contacts Where to Buy/Rent