Telecommunications experiments, e.g., amplitude modulation and demodulation; frequency modulation and demodulation, pulse-width modulation and demo- dulation; pulse code modulation encoding and decoding; amplitude-shift keying, frequency-shift keying, phase-shift keying; heterodyne receiver, equivalent circuits and impedance of transmission line; optical communications; fiber optic cable splicing and OTDR testing; transmission and reflection on transmission line; network diagnostic commands, web server services