Question: What do Timex Sinclair 2048 and IBM PCjr have in common?

Context paragraphs:
IBM PS/1: The IBM PS/1 is a brand for a line of personal computers that marked IBM's return to the home market in 1990, five years after the IBM PCjr.  It was replaced by the IBM Aptiva in September 1994.

Timex Sinclair: Timex Sinclair was a joint venture between the British company Sinclair Research and Timex Corporation in an effort to gain an entry into the rapidly growing early-1980s home computer market in North America.  The choice of partnership was natural, as Timex was already the main contractor for manufacture of Sinclair's ZX81 and ZX Spectrum computers at its Scottish plant in Dundee.  It was Timex of Portugal, though, that took on the R&D and the local manufacturing of the models to be exported to the U.S. Although both Timex of Scotland and Timex of Portugal were full subsidiaries of Timex, internal rivalry, whether unintended or purported, meant there was little sharing between the two plants.  Timex of Portugal also sold the Timex Sinclair models in Portugal and Poland under the Timex Computer brand.

IBM PCjr: The IBM PCjr (read "PC junior") was IBM's first attempt to enter the home computer market.  The PCjr, IBM model number 4860, retained the IBM PC's 8088 CPU and BIOS interface for compatibility, but various design and implementation decisions led the PCjr to be a commercial failure.

Timex Sinclair 2048: The Timex Sinclair 2048 although never produced, was to be an improved version of the Sinclair ZX Spectrum computer.  It was not released by Timex Corporation because of TS1500 failure.  According to an early Timex Sinclair 2000 computer flyer, it would be a cut-down TS2068 with 48 KB of RAM and advertised as a 48 KB memory machine (The TS2068 might have been called the 2072 because of the add of 24 KB ROM + 48 KB RAM = 72KB).

ZX81: The ZX81 is a home computer produced by Sinclair Research and manufactured in Scotland by Timex Corporation.  It was launched in the United Kingdom in March 1981 as the successor to Sinclair's ZX80 and was designed to be a low-cost introduction to home computing for the general public.  It was hugely successful, and more than 1.5 million units were sold before it was discontinued.  The ZX81 found commercial success in many other countries, notably the United States, where it was initially sold as the ZX-81.  Timex manufactured and distributed it under licence and enjoyed a substantial but brief boom in sales.  Timex later produced its own versions of the ZX81 for the US market – the Timex Sinclair 1000 and Timex Sinclair 1500.  Unauthorised clones of the ZX81 were produced in several countries.

Komputer 2086: The Unipolbrit Komputer 2086 was a Polish version of the home computer Timex Sinclair 2068, produced by a joint venture of the Polish Unimor and Timex Computer of Portugal.  The machine wasn't 100% ZX Spectrum-compatible (like all other Timex Sinclair versions) and a "Spectrum Emulation" cartridge was available (usually bundled).

Timex Sinclair 2068: The Timex Sinclair 2068 (TS2068), released in November 1983, was Timex Sinclair's fourth and last home computer for the United States market.  It was also marketed in Argentina, Portugal and Poland, as the Timex Computer 2068.

Timex Sinclair 2050: The Timex Sinclair 2050 (TS2050) was a computer modem built by Westridge for Timex Computer Corp.  Very few were sold with Timex Sinclair label, most with the designed Timex case was sold with the label Westridge 2050 because Timex exited the computer market when the modem started to be manufactured.  A lot of people bought the modem board and made custom casing.

Timex Sinclair 1000: The Timex Sinclair 1000 (TS1000) was the first computer produced by Timex Sinclair, a joint venture between Timex Corporation and Sinclair Research.  It was launched in July 1982, with a US sales price of US$99.95, making it the cheapest home computer to date; it was advertised as "the first computer under $100".  The computer was aimed at regular home users.  Unlike earlier computers aimed at home users, the TS1000 was not a kit which had to be soldered and assembled.  As purchased, the TS1000 was fully assembled and ready to be plugged into the users' home TV (which served as a video monitor).  The TS1000 was a slightly-modified version of the Sinclair ZX81 with an NTSC RF modulator, designed for use with North American TVs, instead of the UK PAL RF modulator which was used for units sold in Portugal.  The TS1000 doubled the onboard RAM from 1 KB to 2 KB.  The TS1000's casing had slightly more internal shielding but remained the same as Sinclair's, including the membrane keyboard.  It had black-and-white graphics and no sound.  It was followed by an improved version, the Timex Sinclair 1500 which had substantially more RAM (16 KB) and a lower price (US$80).  However, the TS1500 did not achieve market success, given that the marketplace was by this time dominated by Commodore, RadioShack, Atari and Apple.

ZX81 character set: The ZX81 character set is the character encoding used by the Sinclair Research ZX81 family of microcomputers including the Timex Sinclair 1000 and Timex Sinclair 1500.  The encoding uses one byte per character for 256 code points.  It has no relationship with previously established ones like ASCII or EBCDIC, but it is related though not identical to the character set of the predecessor ZX80.

Supporting paragraphs: Timex Sinclair 2048 IBM PCjr
Answer: computer