expansion hardware. It also had the AY sound output routed to the monitor/TV speakers instead of the internal twitter. The software developed for the TC 2068 is completely compatible with the T/S 2068, since the ROMs weren't altered. Timex of Portugal also developed a ZX Spectrum "emulator" on cartridge form that mapped the first 16 KB exactly like the earlier TC 2048 computer did. Several other upgrades were made available, including a BASIC64 cartridge that enabled the TC 2068 to use high resolution (512x192) modes. Despite having an AY-3-8912 sound chip, it's not connected in the same ports as in the ZX Spectrum 128K, rendering the TC 2048 incompatible with the AY sound that the Spectrum 128K games produced. Due to all its advantages compared to the usual T/S 2068, a North American company, Zebra Systems, licensed the Timex TC 2068 and sold it in the United States as the Zebra Silver Avenger. They also sold the FDD 3000 as the Zebra FDD 3000 in a silver case (as opposed to the European black cases) to match their colour scheme. Timex of Portugal was working on a successor to the TC 2068 called the TC 3256, using a Z80A CPU and featuring 256 KB of RAM, which would feature a ZX Spectrum BASIC operating mode and a CP/M operating mode, but the company pulled the plug on its development as the 8-bit market was no longer profitable by the end of 1989. Only one complete and fully working prototype of the TC 3256 was made. In India, Deci Bells Electronics Limited introduced a licensed version of the Spectrum+ in 1988. Dubbed the "dB Spectrum+", it did reasonably well in the Indian market, selling over 50000 units and achieving an 80% market share. Unofficial clones Numerous unofficial Spectrum clones were produced, especially in the Eastern and Central European countries (e.g. in USSR (called ), Romania, and Czechoslovakia) where several models were produced (such as the Tim-S, HC85, HC91, Cobra, Junior, CIP, CIP 3, Jet, Didaktik Gama), some featuring CP/M and a 5.25"/3.5" floppy disk. There were also clones produced in South America (e.g. Microdigital TK90X and TK95, made in Brazil and the Czerweny CZ, made in Argentina). In the Soviet Union, ZX Spectrum clones were assembled by thousands of small start-ups and distributed through poster ads and street stalls. Over 50 such clone models existed. Some of them are still being