CoolMasterNet FAQ

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How to make connection from PC

We suggest to use Putty - a simple and free terminal program. Connection can be done via RS232 or TCP/IP.

RS232 Connection TCP/IP Connection
Determine the number of your PC's RS232 port Determine the IP address of CoolMasterNet. It is showed on LCD screen
Run and configure Putty as shown below
Click Open and start communicating with CoolMasterNet

How do I change a name of the Indoor unit on LCD screen

Below command will give Indoor unit L1.101 a name "Room 1"

>props L1.101 name Room 1

To remove name and return to L1.101

>props L1.101 name_

Space after name is vital.

How do I make Indoor unit invisible on LCD screen

Below command will make Indoor unit L1.101 invisible on LCD screen

>props L1.101 visible 0

To make it back visible:

>props L1.101 visible 1

Take into account the fact that invisibility is related only to LCD screen and it does not affect ls command output

How do I set Indoor unit set temperature limits

Below command will limit Indoor unit L1.101 set temperature range to 18C..26C

>props L1.101 tlim 18 26

CoolMasterNet will force set temperature to be inside the limits even if it is changed external by central controller or local wired controller.
To eliminate limits:

>props L1.101 tlim 0 0

How to change or disable CoolMasterNet startup melody

To get list of supported melodies run:

>set melody

0 - Murka
1 - Gena
2 - Sun
3 - The End
4 - Pogoda
5 - Silence

Default melody is '0'. To change melody use below command:

>set melody 5


This specific melody code '5' will make CoolMasterNet silent.


How do I change IP address and/or other network settings

IP network configuration is made with ifconfig command described in PRM document.

HVAC Connection

How to provide DC output on line L1

For Daikin or Mitsubishi Electric Non—VRV/VRF equipment, DC voltage supply by CoolMasterNet might be required for proper operation. Before enabling DC output from CoolMasterNet make sure there is no DC voltage on HVAC communication line. If no DC voltage detected: Daikin 14-16V DC, Mitsubishi 28-30V DC, do following:

  • Disconnect CoolMasterNet from power and HVAC line.
  • Change the dip switches S1 and S2 as shown below.
Daikin Mitsubishi
CM5-dips-DK-S1S2.png CM5-dips-ME-S1S2.png
  • Turn ON the power for CoolMasterNet and connect it to HVAC line.
  • Issue below command:
>line DCOUT L1 +

and power reset CoolMasterNet


Daikin wired remote weekly schedule has gone

Local Daikin wired remotes have weekly schedule function. When any central controller is connected (CoolMasterNet, DCS302, I-Touch, e.t.c) – this function is disabled by default. In BRC1D, you can set the 1B.5 field setting to 01, and get the schedule working again, even if central controller is connected.

Modbus RTU

How to enable Modbus RTU on line L3

Below command will enable Modbus RTU functionality on line L3.

>line type L3 CG5

CG5 stands for "CoolGate5", which is a new Modbus RTU implementation in CoolMasterNet (see details). There is also a CG4 option which will enable an implementation backward compatible with a legacy "CoolGate" device.

How to query or change Modbus Slave Address

Modbus Slave Address is available via line command.


L1: SA U00/G05 myid:E5 Simul(5)
Tx:0/0 Rx:0/0 TO:0/0 CS:0/0 Col:0/0 NAK:0/0
L2: DK Slave U00/G00 myid:0B
Tx:0/0 Rx:0/0 TO:0/0 CS:0/0 Col:0/0 NAK:0/0
L3: CG5 Modbus Address:0x40(64) 9600_8N1
Tx:0/0 Rx:0/0 TO:0/0 CS:0/0 Col:0/0 NAK:0/0
L4: Unused
Tx:0/0 Rx:0/0 TO:0/0 CS:0/0 Col:0/0 NAK:0/0
L5: Unused
Tx:0/0 Rx:0/0 TO:0/0 CS:0/0 Col:0/0 NAK:0/0
L6: Unused
Tx:0/0 Rx:0/0 TO:0/0 CS:0/0 Col:0/0 NAK:0/0
L7: LG Master U00/G00
Tx:0/0 Rx:0/0 TO:0/0 CS:0/0 Col:0/0 NAK:0/0
L8: Unused
Tx:0/0 Rx:0/0 TO:0/0 CS:0/0 Col:0/0 NAK:0/0

To change Modbus Slave Address use line command as shown below:

>line myid L3 50

This command will set Modbus Slave Address 0x50(hexadecimal)


How to change names of Indoor Units (zones)

STEP1: Tap/Click "Settings" icon STEP2: Tap/Click "Edit Names" icon STEP3: Edit names. Tap/Click Save
CoolRemote-EN1.png CoolRemote-EN2.png CoolRemote-EN3.png

How to change Celsius/Fahrenheit temperature presentation

STEP1: Tap/Click "Home" icon STEP2: Tap/Click "User" icon STEP3: Change "Temperature Scale"
CoolRemote-CF1.png CoolRemote-CF2.png CoolRemote-CF3.png

How to change setpoint temperature limits

Tap/Click "Settings" icon
Scroll the screen to reach desired indoor unit
Tap/Click on indoor unit
Tap/Click "Temperature limits"
Change limits
Tap/Click "Save"
CoolRemote-EN1.png CoolRemote-TL3.PNG CoolRemote-TL2.PNG CoolRemote-TL1.PNG


White Screen after power up


  • Move the DIP switch P4 to ON position and back to OFF position a number of times. This is to make sure the DIP switch is properly shorted. Make sure the DIP switch P4 is finally OFF. Reset the power again.
  • Disconnect power supply and connect CoolMasterNet to USB to power it from USB host. If USB connection eliminates the "white screen" issue, the problem is with a power supply. Try to find another compatible power supply.