> Dongles. Even though all computers now have built-in Bluetooth, many Bluetooth accessories today still ship with proprietary dongles. I assume this is because the manufacturer was worried about inconsistencies or incompatibilities between their own Bluetooth implementation and your computer’s built-in Bluetooth hardware/drivers.
No, in most cases where you see dongles (keyboards, mice, gamepads) it’s because the dongle is not speaking Bluetooth to the device, but rather a “raw” pre-paired fixed-frequency RF wire protocol. Devices connected by such dongles (usually marketed as just being “wireless” rather than being “Bluetooth” devices) are basically electrically connected to your computer—just with an RF-modulated bridge stage for the electrical signal path. There’s no “wireless controller” or “modem” in these peripherals; they’re just letting the signal path flow out the antenna.
The disadvantage of these (besides the inconveniences of a dongle) is that these “raw” RF protocols provide no consideration for interference with one-another, besides maybe being e-fused to each operate on a different randomized sub-channel of the commercial-use 2.4GHz band. This means that you can’t have very many of these devices operating in the same “shared medium” (e.g. the same open office); and in fact, a channel collision for these devices won’t just interfere with one-another; they’ll often—lacking any device-ID header or per-device encryption key—just plain interoperate with one-another, with your “wireless” keyboard dongle picking up the typing of some coworker’s “wireless” keyboard! (They’re a lot like RF TV remotes in this regard.)
Note that devices that market themselves as Bluetooth but also come with a dongle are either 1. lying, and don’t actually use Bluetooth; or 2. have Bluetooth and “wireless” as separate modes. There are good reasons to offer both as separate modes:
• Compatibility. “Wireless” devices just look like USB devices, so you can use them to e.g. config your BIOS; or talk to any machine that can speak USB1.0, e.g. some old Win98 beige box. And plugging the dongle into a KVM is just like plugging a USB-connected device into a KVM; you can switch your keyboard’s “focus” between hosts using the KVM, without the host itself needing to re-pair with the peripheral. Switching Bluetooth peripherals around by having the Bluetooth controller on the KVM is much more fraught process.
• Battery life. Bluetooth, at least before BTLE, burned energy to a far greater extent than the “wireless” protocols—mainly because the “wireless” protocols aren’t spending any energy on background activities like identity announcement for re-pairing, or frequency-hopping for better SNR. (This is why you see “wireless” peripherals that last months on AAAs, but all Bluetooth devices shipping with Lithium cells: the Bluetooth peripherals need charging frequently-enough that the number of AAAs they consume would be untenable.)
• Latency. No e-sport player would ever use a Bluetooth peripheral, since the Bluetooth input path often adds one or more in-game frames of latency (relative to the USB input path), before the input hits the game’s physics engine. “Wireless” peripherals have no such problem.
No, in most cases where you see dongles (keyboards, mice, gamepads) it’s because the dongle is not speaking Bluetooth to the device, but rather a “raw” pre-paired fixed-frequency RF wire protocol. Devices connected by such dongles (usually marketed as just being “wireless” rather than being “Bluetooth” devices) are basically electrically connected to your computer—just with an RF-modulated bridge stage for the electrical signal path. There’s no “wireless controller” or “modem” in these peripherals; they’re just letting the signal path flow out the antenna.
The disadvantage of these (besides the inconveniences of a dongle) is that these “raw” RF protocols provide no consideration for interference with one-another, besides maybe being e-fused to each operate on a different randomized sub-channel of the commercial-use 2.4GHz band. This means that you can’t have very many of these devices operating in the same “shared medium” (e.g. the same open office); and in fact, a channel collision for these devices won’t just interfere with one-another; they’ll often—lacking any device-ID header or per-device encryption key—just plain interoperate with one-another, with your “wireless” keyboard dongle picking up the typing of some coworker’s “wireless” keyboard! (They’re a lot like RF TV remotes in this regard.)
Note that devices that market themselves as Bluetooth but also come with a dongle are either 1. lying, and don’t actually use Bluetooth; or 2. have Bluetooth and “wireless” as separate modes. There are good reasons to offer both as separate modes:
• Compatibility. “Wireless” devices just look like USB devices, so you can use them to e.g. config your BIOS; or talk to any machine that can speak USB1.0, e.g. some old Win98 beige box. And plugging the dongle into a KVM is just like plugging a USB-connected device into a KVM; you can switch your keyboard’s “focus” between hosts using the KVM, without the host itself needing to re-pair with the peripheral. Switching Bluetooth peripherals around by having the Bluetooth controller on the KVM is much more fraught process.
• Battery life. Bluetooth, at least before BTLE, burned energy to a far greater extent than the “wireless” protocols—mainly because the “wireless” protocols aren’t spending any energy on background activities like identity announcement for re-pairing, or frequency-hopping for better SNR. (This is why you see “wireless” peripherals that last months on AAAs, but all Bluetooth devices shipping with Lithium cells: the Bluetooth peripherals need charging frequently-enough that the number of AAAs they consume would be untenable.)
• Latency. No e-sport player would ever use a Bluetooth peripheral, since the Bluetooth input path often adds one or more in-game frames of latency (relative to the USB input path), before the input hits the game’s physics engine. “Wireless” peripherals have no such problem.