ECS L4S5A3 Manual page 27

COM2: Onboard serial port connector
Connect a serial port extension bracket to this header to add a second serial
port to your system.
Pin Signal Name
1 NDCDB
2 NSINB
3 NSOUTB
4 NDTRB
5 GND
6 NDSRB
7 NRTSB
8 NCTSB
9 NRIB
10 Key
(optional)
Function
Data carry detect
Serial Data In
Serial Date Out
Data terminal ready
Ground
Date set ready
Request to send
Clear to send
Ring Indicator
Key
23