Liebert EM User Manual

All ports are on the back of the OpenComms EM. The port placement and port labels differ for each 

model. Refer to Figure 2 for your model.

• Connect the DC power adapter to the DCN/Power port on the back of the OpenComms EM, as 

shown in Figure 2. When power is connected, the Power indicator on the front is ON (red).

• Connect a straight-through CAT5 Ethernet cable from your 10 Mbit network to the Ethernet/ETH 

port on the back of the OpenComms EM (see Figure 2). 

• When the unit is connected to an active network, the Link/Cx indicator on the front is ON (green). 

• If using a modem, connect an RJ45 cable from a modem to the Modem port on the back of the unit 

(see Figure 2). Also refer to 6.1 - Modem Setup and Pinout Guide. 

• When the unit is connected to a modem, the Activity/Modem/Mdm indicator on the front is ON 

(green). 

Use a sensor—temperature, humidity, combination temperature & humidity or water detection (see 

Table 3)—or a contact closure cable (see 6.2 - Contact Closure Cable Pinout Guide). 
For a contact closure cable, the orange/white and white/orange wires must be tied together to form the 

common. The blue/white wire is the contact that may be defined as either Normally Open or Normally 

Closed.

• Connect a sensor or contact closure cable to any sensor port—for example, Sensor 1—shown in 

Figure 2. These connections may be made in any order; the ports are identical and are configured 

to accept and recognize all types of sensors. 

• When a sensor or contact closure cable is connected properly to any sensor port, the corresponding 

Sensor indicator on the front is ON (green).

Use the serial cable provided with EM PDU controllers (available separately for vEM-14 controllers), 

or see 6.3 - Serial Cable Pinout Guide (EM PDU & vEM-14 Controllers).

• Connect the six-wire end of the serial cable into the RS232 port of an MP Advanced power strip.
• Connect the other end (eight-wire) of the serial cable to either serial port (Serial 1 or Serial 2) of 

the OpenComms EM, shown in Figure 2. 

• When a cable is connected properly to either port, the corresponding Serial 1 or Serial 2 indicator 

on the front is ON (green).