748 Russell Info Sci Calendar Manager - System Port

748 is a System Port. Transport Protocol TCP UDP , 748 Service Name ris-cm, Service Name Description: Russell Info Sci Calendar Manager.

Port	Protocol	Service Name	Description	Source
748	TCP UDP	ris-cm	Russell Info Sci Calendar Manager	IANA
748	TCP UDP		Mac OS X RPC-based services, Used by NetInfo, for example	Apple.com
748	TCP UDP	ris-cm	Russell Info Sci Calendar Manager	bekkoame

Port	Service Name	Description
1454	interhdl-elmd	interHDL License Manager IANA assigned this well-formed service name as a replacement for "interhdl_elmd".
3055	policyserver	Policy Server
4138	nettest	nettest
4148	hhb-handheld	HHB Handheld Client
4650		Unassigned
6008	x11	X Window System
6278		Unassigned
6733		Unassigned
6738		Unassigned
7091		Unassigned

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