The IEU11, IEQ11, and IEC 11 are Interfaces that conform to the IEEE STD. 488-1978 for compliant test equipment. The IEU11 and IEC 11 are for UNIBUS based systems while the IEQ11 is designed for Q-bus systems. The IEUll and IEQ11 incorporate two independent general purpose interface bus (GPIB) con- trollers. Each controller is capable of supporting up to 15 instruments, including the controller Card Cage Wide Ultra-2/Ultra-3 401529-001 itself. This gives the user the ability to connect up to 28 instru- ments to a single module. The Card Cage Wide Ultra-2/Ultra-3 401529-001 is a single controller that connects up to 15 instruments, including the controller itself. The IEU11, IEQ11, and IEC11 are bit-parallel byte-serial controllers that can perform transfers in either pro- gram interrupt or Card Cage Wide Ultra-2/Ultra-3 401529-001 mode. DMA is standard with the IEU11 and the Card Cage Wide Ultra-2/Ultra-3 401529-001 11. It is optional with the IEC 11. Each independent bus provides system controller, controller-in-charge, talker, and listener capabilities. Termination of data transfers are by Card Cage Wide Ultra-2/Ultra-3 401529-001 or byte count. The IEU11 and the IEQ11 also offer termination of data transfers by match characters.