540 uucpd - System Port | Service Name:uucp

540 is a System Port. Transport Protocol TCP UDP , 540 Service Name uucp, Service Name Description: uucpd.

Port	Protocol	Service Name	Description	Source
540	TCP UDP	uucp	uucpd	IANA
540	TCP		UUCP (Unix-to-Unix Copy Protocol),Official	wikipedia
540	TCP UDP	uucp	uucpd	bekkoame

Port	Service Name	Description
1113	ltp-deepspace	Licklider Transmission Protocol
1385	atex-elmd	Atex Publishing License Manager IANA assigned this well-formed service name as a replacement for "atex_elmd".
1786	funk-logger	funk-logger
2641	hdl-srv	HDL Server
2654	corel-vncadmin	Corel VNC Admin IANA assigned this well-formed service name as a replacement for "corel_vncadmin".
4028	dtserver-port	DTServer Port
4270	vrml-multi-use	VRML Multi User Systems
4905		Unassigned
5249	caaclang2	CA AC Lang Service
5408	foresyte-sec	Foresyte-Sec

A port is an endpoint of communication in an operating system. While the term is also used for hardware devices, in software it is a logical construct that identifies a specific process or a type of service.

Port numbers are assigned in various ways, based on three ranges: System Ports (0-1023), User Ports (1024-49151), and the Dynamic and/or Private Ports (49152-65535);

The Well Known Ports are assigned by the IANA and on most systems can only be used by system (or root) processes or by programs executed by privileged users. Ports are used in the TCP [RFC793] to name the ends of logical connections which carry long term conversations. For the purpose of providing services to unknown callers, a service contact port is defined. This list specifies the port used by the server process as its contact port. The contact port is sometimes called the "well-known port". To the extent possible, these same port assignments are used with the UDP [RFC768]. The range for well-known ports managed by the IANA is 0-1023.
DYNAMIC AND/OR PRIVATE PORTS Registered Ports are those from 1024 through 49151.
The Dynamic and/or Private Ports are those from 49152 through 65535