Liebert EM User Manual

The back of the OpenComms EM, shown in Figure 2, has an input power source, sensor ports, a 

modem port and an Ethernet port. The EM PDU and vEM-14 controllers have serial ports, and 

vEM-14 controllers also have 10 dry contact inputs. 

Indicators on the front of the unit show the status of input power 

and other connections (see Figure 1).

Sensor ports to connect compatible sensors: 
• Temperature sensor 

(provided with TMNET & TMPDUNET kits)

• Temperature & humidity combination sensor 

(provided with THCMNET & THCMPDUNET kits)

• Humidity, water detection or dry-contact sensor

(available separately)

2.3.4: Connect Sensors
5.3:

Port for connection to a modem. 
• Requires RJ45 cable (customer-supplied)

Serial 1 and Serial 2 ports to connect serial devices 

(EM PDU and vEM-14 controllers). 
• Requires serial cable (one provided)

Port for connection to an Ethernet network. 
• Requires RJ45 cable (customer-supplied)

2.3.2: Connect to an Ethernet Network
5.7.1: Network Connectivity

Power connection for the OpenComms EM. 
• Requires 9VDC

10 dry contact inputs for auxiliary devices (vEM-14 controller). 
• Requires Form C dry contacts

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