Do accessories have noise cancellation (NC)?

Some accessories provide noise cancellation via the handset only (single-mic & near-end NC), and other accessories include DSP, noise suppression or cancellation. Specifications are provided in datasheets.

Are RSMs compatible with a wired headset?

Each RSM has a 3.5mm connector to connect a wired listen-only earpiece. The optional listen-only earpiece redirects the receive audio, while still transmitting audio through the RSM. This is necessary