Technical Specifications Minimum line current: 15 mA, directly from the handset Minimum line voltage (on-hook): 22 V DC voltage drop (off-hook): 1 MΩ (U = 25–100 V) Off-hook impedance: 220 Ω + 820 Ω in parallel, 115 nF, 15 to 60 mA Attenuation: > 14 dB, 15 to 60 mA Bandwidth: 300 to 3500 Hz, 15 to 60 mA Ringing impedance: > 2 kΩ, C = 0.47 µF, 25 to 50 Hz Pulse dialing: 40 / 60 ms DTMF tone levels: -9.0 dB (+2.0/-2.5 dB) and -11.0 dB (+2.5/-2.0 dB), 15 to 60 mA Overvoltage protection (A/B line differential): 1000 V (8 / 20 µs) Note: Any ring sequence is acceptable Minimum voltage: 9 V AC or DC Maximum voltage: 24 V AC or DC Maximum current: 1 A AC or DC Open contact resistance: ≥ 400 kΩ Closed contact resistance: approx. 0.5 Ω Fuse: Resettable Power supply voltage: 12–24 V DC (external source) Maximum switching current: 200 mA Universal version dimensions: 65 × 130 × 24 mm Compact version dimensions: 100 × 185 × 16 mm Operating temperature range: -20 to +70 °C