Black Box Corporation MC167A power adapter

50-pin telco splice block

The Black Box MC167A is a pre-wired splice block with a 66-type layout and two connector clips. It terminates 50 telco female ports in a compact unit suited to structured wiring closets and patching frames. Installers use it to cross-connect or distribute voice-grade circuits without soldering. The block ships new and carries a lifetime guarantee.

Practical limits of 50-pin telco interface

The 50-pin telco connector handles up to 25 pairs on a single block, so larger pair counts require additional blocks or the 25-pair variant. Each clip accepts solid conductors sized for standard punch-down tools; stranded or oversized wire may not seat reliably. The interface provides no shielding, so runs near high-current cables can pick up noise. No active components are present, so the block adds no signal conditioning or amplification.