The Stedcom Black Max is a dust-proof, hose-proof, heavy-duty, wall-mounted telephone specifically designed to resist the harsh conditions encountered in mining and industry.
The casting is injection molded in ABS . The keypad is sealed with a transparent silicon rubber overlay; the handset is of harden injection mold and the cord of tough industrial P.V.C., attached with a dustproof Plastic gland, (also available with a Stainless Steel Cord) Housing attached with a dustproof metal gland). Both transmitter and receiver capsules are of the dynamic type.
Ring: Voltage 25 – 110 V.A.C.
Ringing via mouthpiece
Dialling: Tone / Pulse switchable. Ratio 2:1 I.D.P. 100 ms.
Speech loop: 25 – 60 V.D.C. Up to 2000-ohm loop.