1688 nsjtp-data - User Port | Service Name:nsjtp-data

1688 is a User Port. Transport Protocol TCP UDP , 1688 Service Name nsjtp-data, Service Name Description: nsjtp-data.

Port	Protocol	Service Name	Description	Source
1688	TCP UDP	nsjtp-data	nsjtp-data	IANA
1688	TCP		Microsoft Key Management Service for KMS Windows Activation,Unofficial	wikipedia
1688	TCP UDP	nsjtp-data	nsjtp-data	bekkoame

Port	Service Name	Description
3457	vat-control	VAT default control
4059	dlms-cosem	DLMS/COSEM
4324	balour	Balour Game Server
5340		Unassigned
5868	diameters	Diameter over TLS/TCP
7017		Unassigned
8473	vp2p	Virtual Point to Point
8893	ddi-tcp-6	Desktop Data TCP 5: NewsEDGE/Web application
9109		Unassigned
9452		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