n These bus buffers feature three-state outputs that, when enabled, have the low impedance characteristics of a TTL output with additional drive capability at high logic levels to permit driving heavily loaded bus lines without external pullup resistors. When disabled, both output transistors are turned off, presenting a high-impedance state to the bus so the output will act neither as a significant load nor as a driver. The ?125 and ?LS125A devices? outputs are disabled when G is high. The ?126 and ?LS126A devices? outputs are disabled when G is lo