Why Can’t Chromecast, Airplay and Bluetooth Get Along?

The hardware and software that help products speak the same language

When engineers design the latest and greatest consumer electronic devices, compatibility becomes an important — though treacherous — conversation. If you’ve read my previous DigiKey blogs, you’ll know I’m a supporter of backward compatibility and a critic of format wars. But I also understand that engineering discussions on ecosystems often boil down to budgets, technology, hardware, logistics, programming, IP, and planning. Wireless communication, in the form of Chromecast, Airplay, Bluetooth, and Wi-Fi, is a great example.

A radio-frequency transceiver compatible with 802.11 a/b/g/n/ac, Bluetooth v4.1 GPIO, I2C, SPI, UART, and USB 5Gbps. (Source: Deepwave Digital, NVIDIA and DigiKey.)

Chromecast and Bluetooth are almost as widely used as Wi-Fi. However, Airplay doesn’t always play nice with others. Apple has relaxed the reigns on which third-parties can utilize its proprietary wireless communication protocol, but it remains a largely closed ecosystem. Alternatively, Google and the Bluetooth Special Interest Group (SIG) have gone the open-source route, enabling a vast array of hardware and software to integrate into the pairs’ ever-growing ecosystems.

The question becomes: Can engineers, and by extension consumers, win by offering products that interface with all these wireless communication technologies?

What wireless communication technologies have in common

At their core, all wireless communication technologies operate the same way. Transmitters take an electronic signal and transform it into a radio frequency wave. The wave is then picked up by a receiver that translates the message back into an electronic signal. Transceivers are devices that can both send and receive these signals. Where Wi-Fi, Chromecast, Airplay, and Bluetooth differ is in how those messages are translated, encoded, and transmitted. In essence, they talk the same way but speak different languages.

From a hardware perspective, engineers can easily design consumer electronics to interact with all four wireless communication protocols, by selecting a transmitter that is compatible with the various frequencies these protocols work at. In other words, ensuring a product can interact with all the protocols is mostly a software challenge.

What separates Wi-Fi, Chromecast, Airplay, and Bluetooth ecosystems?

Bluetooth is really its own thing. It utilizes the 2.4 GHz frequency band to enable nearby electronics to talk to each other. Bluetooth Classic limits this communication between two devices but has a data cap of 3 Mbps. Bluetooth Low Energy (BLE) uses less power, as its name suggests, but also enables multiple devices to talk to each other at the same time. The downside to BLE is that it has a data cap of 2 Mbps. When engineers design consumer electronics, it’s possible to select a transceiver that is compatible with Bluetooth but not Wi-Fi, Chromecast or Airplay.

Ironically, Wi-Fi is at the core of both Chromecast and Airplay; they all operate at the 2.4 GHz and 5 GHz frequency bands. The two competing technologies piggyback on Wi-Fi to enable multiple systems — on the same network — to communicate. This commonality is why various software solutions exist enabling Chromecast devices to talk to Airplay devices, and vice versa, without hardware expansions. This commonality also explains why any transceiver that is compatible with 802.11 a/b/c/g/n can theoretically work with Wi-Fi, Chromecast, or Airplay. However, that transceiver may or may not be able to connect to Bluetooth. The bandwidths for Wi-Fi 6 caps at about 9,600 Mbps, Airplay at about 54 Mbps, and Chromecast at 60 Mbps.

The main difference between Chromecast and Airplay is that when streaming data, Google’s technology instructs equipment to access the stream directly. Airplay devices, on the other hand, ingest the stream and then transmit that audio/visual data to the equipment. This is why it’s possible to turn off an Android phone when using most Chromecast functionalities; meanwhile Apple devices need to remain on for all Airplay functionalities. Said another way, Chromecast devices act like a remote control while Airplay acts like a cable box.

Summary

It’s worth pointing out that since Chromecast devices access a stream directly, they tend to experience better visual and audio qualities than with Airplay or Bluetooth. So, unless you are designing a product to directly target the Apple and/or Bluetooth communities, it’s a good choice to ensure the design is Chromecast compatible.

For more information on transceiver technology, and the wireless systems they are compatible with, visit the DigiKey’s product list.