The talk at the FOSDEM conference in 2023 was given by Charles Brozegard on binary pattern matching in Elixir and Erlang. Charles explained that when working with devices in the Internet of Things realm, he often has to communicate with them using custom binary dialects. He highlighted the benefits of using Elixir for this kind of work and discussed how binaries are sequences of bits that can be written in different notations such as binary, decimal, and hex. He introduced the concept of a codec, which is a translation layer that encodes and decodes data structures into binary sequences. Charles then explained the basics of using bit syntax in Elixir to encode and decode binary data, showcasing examples with a binary dialect he invented called T-Box. He also mentioned that there are other tools and libraries available for working with binaries. In the Q&A section, attendees asked about streaming data and passing of messages, and Charles mentioned that there are patterns and libraries, such as the framing behavior for streams and the Redis library, that can handle these scenarios. Overall, the talk provided an introduction to binary pattern matching in Elixir and Erlang for communicating with IoT devices.