SATO CL4NX Programming Reference Manual page 698

TCP connection queue: Enabled
While connected to one host, the printer returns an acknowledgement response (ACK) to a
connection request (SYN) from another host.
* Only 1 port connection of Status 3, 4, 5 is supported when TCP connection queue is enabled.
Host 2
CONNECT
CLOSE
Parent topic LAN/Wireless LAN
Host 1
CONNECT
SYN
ACK
CLOSE
FIN
FIN ACK
696
Printer
SYN
ACK
FIN
FIN ACK
ACCEPT
Host 1 and printer
are connected
CLOSE
Host 2 and printer
are connected
CLOSE