TENET (Edu Network - Prototype)

The TENET (Timex Educational NETwork) was a Local Area Network (LAN) developed by Timex of Portugal with the primary use to be in schools and it consisted of a network similar to the ZX Net provided by the Sinclair ZX Interface 1 but much more advanced. Programmers could develop programs or games to take advantage of the network.

The network consists of a Master station with a Timex FDD 3000, a Timex 2080 printer, and to a maximum of 24 client stations. The Master station can control all client stations, load programs/data, halt, reset, retrieve the screen, and send messages to any client station. Client stations can be given permission to access a file on the FDD 3000 and/or to print data on the printer and send messages to any station.

The machine shown (it’s currently located in the LOAD “ZX” Museum) here is one of the first prototypes made for the network test. A later version more refined with a gate array made by Thompson was made much smaller in an interface form instead of a daughter board inside the computer. Later the TENET system was incorporated into the Timex Computer 3256.

  • Network topology of 2 wire bus
  • Updo 25 stations (1 master + 24 clients)
  • Maximum network length 100 meters
  • Data transmission is asynchronous with an 11-bit frame at 187.500 bits/second
  • Network protocol packed switched master-slave with error detection and packet retransmission
  • Interface hardware with a single chip microcomputer (8031) with 2 port TAM for communication with the host computer

BASIC extensions available at the Master station:

  • CLEAR AT resets a station
  • RANDOMISE & USR force a machine code jump at a station
  • LOAD & reloads a station with basic or machine code
  • VERIFY AT checks a station status
  • PRINT #6 sends a message

Basic extensions available at the Client stations:

  • OPEN# & remote file open
  • CLOSE# & remote file close
  • PRINT & remote file write
  • INPUT & remote file read
  • MOVE & prints a file on the master’s printer
  • SAVE & saves a file on the master’s disk drive
  • LOAD & loads a file from the master’s disk drive
  • MERGE & combines a BASIC program from the master’s disk drive
  • PRINT #6 sends a message

Other functions are available from machine code for general purposes, memory-to-memory transfers, and message passing.