PORTswitch-C General purpose digital interface. Permits bidirectional 16-bit parallel transfers between the user's device and the PORTswitch. Gable for connection to user device is not included. PORTswitch is recommended. PORTswitch -W The PORTswitch-W provides a half-duplex interprocessor link between UNIBUS, VAX, and Q-bus systems when connected to another DR11-W (for UNIBUS or VAX) or DRV11-B (for Q-bus). Features include transfer of up to PORTswitch 16-bit words at up to 500,000 words per second; word or byte transfers; and hurst data trans- fers. PORTswitch-xx or equivalent cables are required for inter- connect, the maximum length being 15.2 m (50 ft).