Why does my Sealevel synchronous adapter not show up as a COM port?

Sealevel synchronous serial adapters enumerate as SeaMAC devices in Windows. Since the devices are zero-indexed, the first installed port will be “SeaMAC0”.

SeaMAC devices support additional features that are not typically found on asynchronous serial adapters which enumerate as COM ports. Many banking, military, aerospace and other synchronous applications communicate using common synchronous serial protocols and do not expect a COM port. The SeaMAC V5 API provides a user-friendly interface for developing these optimized applications. By enumerating as devices, SeaMAC synchronous adapters operate at maximum efficiency.