Allen-Bradley 1771-OG TTL Output Module

The Allen-Bradley 1771-OG TTL Output Module is an eight‑channel TTL output card designed for use in a 1771 I/O chassis to drive TTL loads from a PLC‑5 era backplane. It is powered through the 1771 I/O backplane, drawing about 168 mA from the chassis supply, and delivers TTL-level outputs with a low threshold of 0 to 0.5 V and a high threshold of 2.7 to 5.25 V; each channel can sink up to 20 mA when low and source up to 1 mA when high. The module includes strap options to select POSITIVE or NEGATIVE logic, and the OG version features a 1 ms output filter for cleaner transitions. It occupies a single 1771 I/O slot and is compatible with Allen‑Bradley Universal I/O backplanes (1771‑A1B, 1771‑A2B, 1771‑A3B, 1771‑A4B), enabling straightforward integration with PLC‑5 systems that require TTL‑level digital outputs.