| T. Humphries | No tapes | No tapes | No books | No hardware |
| T. J. Thomas | No tapes | No tapes | No books | No hardware |
| TV Services of Cambridge | No tapes | No tapes | No books | No hardware |
| Tasman Software | No tapes | No tapes | No books | No hardware |
| Taurus | No tapes | No tapes | No books | No hardware |
| Technomatic | No tapes | No tapes | No books | No hardware |
| Temptation Software | Tapes | No tapes | No books | No hardware |
| Texgate | Tapes | No tapes | No books | No hardware |
| Thomas B. Woods | Tapes | No tapes | No books | No hardware |
| Thurnall Electronics | No tapes | No tapes | No books | Hardware |
| Timedata | Tapes | No tapes | Books | Hardware |
| Timeworks | Tapes | Tapes sorted by code | No books | No hardware |
| Timex | Tapes | Tapes sorted by code | No books | Hardware |
| Timothy Skinner | No tapes | No tapes | No books | No hardware |
| Transform | No tapes | No tapes | No books | No hardware |