HelixNet HMS-4X Cold Standby Unit

HelixNet version 4.1 and onward allows a HMS-4X in any linking mode (Disabled, Link Master or Link Member) to be swapped for an identically configured cold standby unit which can be swapped in - one unit connected to the system at a time - without additional user interaction (such as pairing or role selection of endpoints).


Primary HMS-4X; The unit normally used to run the HelixNet system

Cold-Standby HMS-4X; The unit that is offline or powered down with an identical configuration to the powered unit. This unit is never running or connected to the system unless its Primary HMS-4X is powered down or disconnected from the system.


To prepare a Cold-Standby HMS-4X;

  • Setup and fully configure the HelixNet system

  • Store the configuration of the HMS-4X you would like to have a Cold-Standby unit from the FRONT PANEL USB connector on the Primary HMS-4X

  • Ensure the Cold-Standby HMS-4X is populated with identical HLI modules as the primary unit

  • Ensure the Cold-Standby HMS-4X is disconnected from any data and audio connections

  • Reset the Cold-Standby HMS-4X to default

  • Recall the stored file from the Primary HMS-4X using the FRONT PANEL USB connector on the Cold-Standby HMS-4X

  • Verify that the Network Settings and Host Name are recalled on the Cold-Standby HMS-4X and identical to the Primary HMS-4X

To change-over to a Cold-Standby HMS-4X;

  • Power down or physically disconnect the Primary HMS-4X from the system

  • Power up or physically connect the Cold-Standby HMS-4X to the system

  • Move all physical connections from the Primary HMS-4X to the Cold-Standby HMS-4X

  • Allow the Cold-Standby HMS-4X to boot-up or connect to the system

The Cold-Standby HMS-4X unit will connect to the Link Group following that all endpoints will connect and load their roles/keys.

  • Talk Keys will come up unlatched

  • Channel listen levels will be reset to unity gain


  • DO NOT allow the Primary and Cold-Standby HMS-4X to be online and connected at the same time!
    The units are on identical IP addresses and mDNS Host Names which will cause issues.

  • If the endpoints do not immediately start to connect to a Cold-Standby HMS-4X (was previously powered on but disconnected from the network) you may need to power-cycle the Cold-Standby HMS-4X to force the network to refresh. Remember that a HMS-4X power-cycle can be initiated by pressing HSET at the same time as the MAIN and PGM.

  • If the Cold-Standby HMS-4X is for a Link Master the Cold-Standby unit should be maintained by recalling its settings following changes to the Link Master.