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Telephone Expansion Board (FXO) (700-26-23) (LAST TIME BUY)

The Telephone Expansion Board (FXO) is one of the option cards available for the Gemini™ Intercom system.


• Standard interface for 4 PSTN lines or other 3rd-party telephony devices

• Allows outside callers to access a Gemini intercom system

• Enables internal users to make and receive outside phone calls

• Auto-answer

• Manual-answer

• Line Access from Intercom Panel

s• Line Access from Other Gemini users with DTMF Capability

Item Code



Line Interference

Number of channels: 4 per card, Max of 4 option cards per Gemini unit

DSP channel usage: 4 DSP IP channels per card

Signalling: Loop start or ground

DTMF: DTMF detection for DDOI routing

Bypass phone operation: Phone is switched out of circuit whenever FXO channel is in use

Line Impedance: CTR21, 600R, 900R or Japan – software selectable

Return loss: >18dB 300-400Hz Protection: FCC pt 68 type B longitudinal surge, 1500V: FCC pt 68 type B metallic surge, 800V

Ring equivalency number: REN <0.2

Longitudinal balance: >60dB (200-1000Hz); 40dB (1000-4000Hz)

Common mode rejection ratio (CMRR): On hook >70dB 50-500Hz Vcm=60Vrms; Off hook >40dB 50-500Hz Vcm=60Vrms

Common mode overload level (CMOL): On hook >300Vrms 50-60Hz; Off hook >250Vrms 50-60Hz

Max trip/ring voltage: 300V (Correct operation not implied) Recommended max 120V

Max loop current: 90mA

Ringing voltage – detect: Typically 22V, min 26V, 17-68Hz

Ringing voltage – no detect: Typically 14V, max 18V, 1768Hz

THD: <1% at 0dBm, 1kHz

Crosstalk: <-85dB (inter-channel and inter-card)

Insertion Loss: 0dB

Nominal line TX level: -9dBm ± 1dB

Input level adjustment: Via software –9dB to +12dB in steps of 1.5dB

Output level adjustment: Via software –34.5dB to +12dB in steps of 1.5dB. Mute option

Freq response: 300Hz – 3200Hz ± 2dB ref to 1kHz (8kHz sampling)


Line: RJ11 2 pin modular jack socket

Bypass Phone: 1 per channel (4)

Phone connector pinout: Pin 3 – tip (B), Pin 4 – ring (A), other pins - unused


Ring Cadence: US Ringtone

Echo Suppression

General: DSP Based adaptive filter providing acoustic & network suppression

Tail length (acoustic): 63.5ms

ERLE: 30dB typical


Operating temperature range: 32° to 122°F (0 to 50°C)

Storage temperature range: -4° to 140°F (-20° to 60°C)

Operating humidity: 20 to 90% at 104°F/40°C non-condensing

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