Networking Technologies

2.4. Modern Role

Modern Role (Broadband Era):

DSL Modems: Use existing phone lines but in a higher frequency band (to avoid voice interference). Digital Subscriber Line (DSL) modems achieve 1–100 Mbps via advanced modulation like DMT (Discrete Multi-Tone).

Cable Modems: Leverage TV coax cables for DOCSIS standards, hitting 1 Gbps+ downstream. They use hybrid fiber-coax (HFC) networks, where the ISP's core is fiber (digital), but the "last mile" to homes is coax (analog-converted).

Fiber Optic Modems (ONTs/ONUs): For GPON/EPON, these handle optical-to-electrical conversion (analog light signals to digital electricity). Speeds exceed 1 Gbps symmetrically.

Mobile/5G Modems: In routers or phones, they modulate data over radio waves (wireless analog medium) for cellular internet.

Satellite Modems: For rural areas (e.g., Starlink), they convert data to/from microwave signals.