Receivers

A receiver is the USB dongle that wireless Logitech devices pair to. OpenLogi detects the receiver on its USB/HID channel, then enumerates the devices paired to it.

Unlike device features (which use HID++ 2.0), receivers are driven through HID++ 1.0 registers and are always addressed at device index 0xFF (RECEIVER_DEVICE_INDEX). They are identified purely by their USB vendor/product ID — openlogi-hidpp's receiver::detect() matches the channel's VID/PID against the known sets and returns a Receiver.

Detection

receiver::detect(chan) returns Some(Receiver) for a known dongle, or None otherwise.

The Lightspeed dongles bundled with G-series devices answer the same HID++ 1.0 registers as Unifying, so they are detected, enumerated, routed, and paired through the Unifying code path — only the user-facing name differs (Lightspeed Receiver). C53F is the nano receiver of wireless mice such as the G305, verified against a G305 (paired device wpid 0x4074); C547 ships with newer devices such as the G915 keyboard and the G502 X LIGHTSPEED, verified against a G915 (wpid 0x407c). C539 is the Lightspeed gaming receiver, listed with the Unifying PIDs because it is routed as one.

Common API

The Receiver enum wraps the concrete receiver kinds and exposes the shared surface:

Errors surface as ReceiverError — UnknownReceiver, or a wrapped HID++ 1.0 Protocol error.

Logi Bolt

The current Logitech receiver. Bolt is BLE-based, pairs up to 6 devices, and authenticates new devices with a passkey before pairing. bolt::Receiver exposes:

Pairing flow

1. discover_devices(Some(secs)) — the receiver emits Event::DeviceDiscoveryDeviceDetails (carrying the device address, kind, wpid, authentication) and Event::DeviceDiscoveryDeviceName for each nearby device.
2. pair_device(slot, address, authentication, entropy) — entropy sets passkey complexity (for mice, the number of left/right clicks the user must enter).
3. The receiver completes pairing and emits Event::DeviceConnection.

Events (bolt::Event)

DeviceKind covers Keyboard, Mouse, Numpad, Presenter, Remote, Trackball, Touchpad, Tablet, Gamepad, Joystick, Headset (plus Unknown).

Unifying

The previous-generation receiver. Unifying pairs up to 6 devices over the proprietary Unifying / DJ protocol; once addressed by their slot index, paired devices speak HID++ 2.0. unifying::Receiver exposes:

Enumerating paired devices (Rust)

use std::sync::Arc;

use hidpp::{
    channel::HidppChannel,
    receiver::{self, Receiver},
};

// chan: Arc<HidppChannel> bound to the receiver's HID interface.
let Some(rx) = receiver::detect(Arc::clone(&chan)) else {
    return; // not a known Logitech receiver
};
println!("{} — {}", rx.name(), rx.get_unique_id().await?);

match rx {
    Receiver::Bolt(bolt) => {
        for dev in bolt.collect_paired_devices().await? {
            // dev: bolt::DeviceConnection — one paired device
            let _ = dev;
        }
    }
    Receiver::Unifying(uni) => {
        let events = uni.listen();
        uni.trigger_device_arrival().await?; // re-fires DeviceConnection events
        while let Ok(event) = events.recv().await {
            // handle unifying::Event::DeviceConnection { .. }
            let _ = event;
            break;
        }
    }
    _ => {}
}

No receiver

Bluetooth-direct and wired devices enumerate as their own inventory — no receiver involved. See Connect a device.