2N Fixed line replacement with 2N SmartGate - Manual v1.1.2 - Manual (Page 79)

Technical Parameters 5.1
79
Telephone connector type RJ 12, 6/2
Line impedance 600 
Loop voltage on hook 48 V DC
Loop current max. 40 mA
Loop resistance max. 800 
Tone frequency adjustable, default 425 Hz
Dialing type tone (DTMF) or pulse
Ringing voltage 42 Vrms 50/25 Hz
Calling line identification CLI during ringing according to ETSI FSK
Tariff pulses f=16/12 kHz ; Umin=100 mVef on 200 
Answer supervision polarity reversal, 12/16 kHz pulses
Telephone Interface FXO (for PBX extension line)
Interface type 2-wire analog, FXO
Telephone connector type RJ 12, 6/2
Line impedance Zr (TBR21) or 600  (According to model of Gateway)
On-hook DC resistance 1 M
Off-hook line current 10 - 65 mA
Off-hook line voltage (typ.) 4,5 V for 25 mA
Dial tone frequency adjustable, default 425 Hz
Dialing type tone (DTMF)
Ringing voltage Min. 20 Vrms 25-50 Hz
Ringing impedance 4 - 10 k / 50 Hz
Dial thru parameters
Voltage drop (typ.) 1,7V / 25 mA
Closed loop resistance (typ.) 6 
SMS Sending Input