The FHF ResistTel is a robust, weatherproof corded telephone specifically designed for use in harsh environmental conditions both indoors and outdoors. The housing is made of glass-fiber-reinforced polyester (GFRP), offering high mechanical strength and weather resistance. The keypad and all metallic components are made of V4A stainless steel, ensuring corrosion protection and long service life. The device features an integrated, 2-line alphanumeric display with pictograms and an integrated hands-free function, enabling comfortable telephony without using the handset. Additionally, the telephone includes a 7-level volume amplifier (0–12 dB(A)) for hearing-aid compatible use, as well as an integrated phonebook with space for up to 50 entries. Optical call signaling enhances visibility of incoming calls. Security is ensured by a PIN lock. The telephone is suitable for wall mounting and features a steel-reinforced handset cord to protect against mechanical damage. The IP66 protection rating (dust- and water-tight, suitable for outdoor use) allows operation at relative humidity up to 98% and within a temperature range of -25 °C to +60 °C. Power supply is via the network. The device is finished in anthracite and measures 266 mm (height) × 227 mm (width) × 135 mm (depth), weighing 5.5 kg.