Technical references
The building blocks, made understandable.
Keep these pages beside you when a guide uses an unfamiliar protocol or physical-layer idea. Each starts with the simplest useful explanation, then adds the detail you need to reason about real systems.
Choose a reference
Read from the beginning or jump straight to the table, exchange or encoding you need.
Electromagnetic spectrum
What electromagnetic waves are, how frequency and wavelength relate, who uses each band, and why spectrum is finite and valuable.
DHCP protocol
How a new device receives an address, subnet, gateway and DNS settings—the DORA exchange, leases, relays and failure modes.
DNS protocol
How names become answers: recursive and authoritative servers, delegation, caching, record types, transport and security.
HTTP protocol
The web’s request-and-response language: methods, URLs, headers, status codes, bodies, caching and HTTP/1.1 through HTTP/3.
TLS protocol
What HTTPS protects, how certificates prove identity, how the TLS 1.3 handshake creates keys, and what TLS cannot promise.
Multiplexing
How many conversations share one medium using frequency, time, wavelength, codes, space, subcarriers, polarisation and antennas.
Multimedia encoding
How video and audio are compressed, what common codecs do, how containers package streams and what controls quality.
Line codes
How bits become electrical or optical symbols: NRZ, Manchester, AMI, block codes and modern multi-level PAM signalling.