Prestel
In 1983, the Prestel messaging service known as “Prestel Mailbox” was launched, initially hosted on the computer known as "Enterprise", and later available from all IRC computers by means of a centralised messaging computer known as "Pandora". This facility extended the original day one concept of “Response Frames” whereby an end user could send a message back to the IP who owned the page via special pages, for example to order goods or services. The user’s name, address, telephone number, and date could be added automatically to the message when the IP set up the response frame by means of codes which triggered extraction of key data from the users account held on the IRC computer. Initially response frames were ingathered by an IP from each IRC individually, but later the facility to collect messages from all IRCs at the UDC from where they could be ingathered centrally was implemented, and with the introduction of Mailbox, they could be retrieved from any IRC.
Port (computer networking)
The term "port number" was not yet used at this time. It was preceded by the use of the term "socket number" in the early development stages of the network. A socket number for a remote host was a 40-bit quantity. The first 32 bits were similar to today's IPv4 address, but at the time the most-significant 8 bits were the host number. The least-significant portion of the socket number (bits 33 through 40) was an entity called "Another Eightbit Number", abbreviated AEN. Today, "network socket" refers to a related but distinct concept, namely the internal address of an endpoint (used within the node only).