1857989-1 is a Hard Metric Backplane PCB Mount Receptacle from the Z-PACK 2mm HM series, designed for board-to-board connections in traditional backplane architectures. This connector features 110 positions arranged in a 22-column by 5-row configuration with a 2 mm centerline pitch and right-angle PCB mount orientation. The receptacle supports data rates up to 1 Gb/s with gold-plated contacts over nickel underplating on a phosphor bronze base material, providing a maximum contact current rating of 1.5 A. The housing is constructed from Polyester GF material with a UL 94V-0 flammability rating and operates over a temperature range of -55°C to +125°C. This connector is ideal for high-speed signal transmission in telecommunications, computing, and industrial backplane systems requiring reliable board-to-board interconnections.