Interface: EngineBind

Per-engine routing hints.

Transport-layer routing is keyed by transport (bind.usb, future bind.tcp) and consumed by the transport implementation. Protocol-layer routing (bind.address) sits as a flat sibling and is consumed by the protocol implementation — opaque to the registry.

USB-composite example (LabelWriter Duo): each engine binds to its own USB interface via bind.usb.bInterfaceNumber.

Protocol-addressed example (LabelWriter Twin Turbo): both engines share the chassis USB endpoint and select via bind.address — for lw-450, bind.address: 1 is encoded as ESC q 0x01 prepended to the job. 'auto' is not a stored value — it is a routing mode in PrintOptions.engine.

If a future protocol grows more than one in-band routing dimension, promote bind.address to bind.protocol: { ... }.

Properties

Property	Type	Description
address?	number	Opaque protocol-layer address; protocol module knows how to encode.
usb?	{ bInterfaceNumber: number; }	USB-composite routing — engine bound to a specific USB interface.
usb.bInterfaceNumber	number	-