Liebert POWER PROTECTION STATIC TRANSFER SWITCH User Manual

Page of 152
Specifications
114
15.2.9 RS-232 Port
The unit is equipped with an RS-232 port for connecting a terminal or PC. 
See Figure 29 for the port’s location. 
See 12.1 - Using the RS-232 Port for instructions on using a PC terminal with the unit.
15.2.10Terminal Port Connections
The system has an asynchronous serial port configured as Data Terminal Equipment for terminal 
access only (half duplex). The CPU services the terminal port with no handshaking. The serial port 
conforms to RS-232 levels with a data format of 9600 Baud, 1 start bit, 8 data bits, and no parity bits. 
The serial port is 1000 Volt DC isolated (non-SELV) and ESD protected to 15kV air discharge. The 
connector is a 6 Pin MTA plug with connections shown below.
A DB9 male connector is added and connected parallel to the 6 position header. It is configured as 
DTE.
Table 22
MTA Plug Pinout
Pin 
Signal Name 
Function / Comments
ISO_GND 
Isolated service terminal ground
ISO_TXD 
Isolated service terminal transmit output
ISO_RXD 
Isolated service terminal receive input
4 NC 
No 
Connection
5 NC 
No 
Connection
6 NC 
No 
Connection
Table 23
DB9 Pinout
Pin 
Signal Name 
Function / Comments
1 NC 
No 
Connection
ISO_RXD 
Isolated service terminal transmit output
ISO_TXD 
Isolated service terminal receive input
4 NC 
No 
Connection
ISO_GND 
Isolated service terminal ground
6 NC 
No 
Connection
7 NC 
No 
Connection
8 NC 
No 
Connection
9 NC 
No 
Connection