Starting with the Tandy 1000 TL/2, XT IDE controllers were integrated onto the motherboard. However, these were incompatible with common AT IDE hard drives. The TL/2, TL/3, RL and RLX all used the XT IDE interface, where the later (and significantly upgraded) RSX was the first and only Tandy 1000 model computer to use a standard AT IDE interface. One option for contemporary users of these systems would be to install and use XT ISA CompactFlash adapters; this is also the most practical way to install a hard drive into a Tandy 1000 EX or HX, using an adapter cable that adapts the male PLUS-style connector to an 8-bit ISA card-edge slot.