14 SSA-424 USER MANUAL
2.6 2-WIRE CALL SIGNAL

2.6.1 CALL SIGNAL CONNECTIONS FOR AUDIOCOM,

RTS TW AND CLEAR-COM

The call signals are superimposed on the audio
signal, so no separate call signal connections are
required. However, make sure that a call enable
switch or jumper is installed for Clear-Com applica-
tions as shown in Figures 5 and 6.

2.6.2 CALL SIGNAL CONNECTIONS FOR OTHER 2-

WIRE COMMUNICATION SYSTEM

Any other 2-wire device must be able to generate
and receive a 20kHz signal superimposed on the
audio as follows:
Balanced Audio Configuration
Pin1: No connection
Pin 2: Balanced 20 kHz + Input/Output
Pin 3: Balanced 20 kHz - Input/Output
SSA-424 Signal Specifications for balanced configu-
ration:
SSA-424 Receive: 20kHz ±100 Hz, 100mV p-p
SSA-424 Send: 20 kHz ±800 Hz, 1V p-p
Unbalanced Configuration 1
Pin 1: 20 kHz Common
Pin 2: 20 kHz Input/Output
Pin 3: No connection
Unbalanced Configuration 2
Pin 1: 20 kHz Common
Pin 2: No connection
Pin 3: 20 kHz Input/Output
SSA-424 Signal Specifications for unbalanced
configurations:
SSA-424 Receive: 20 kHz ±100 Hz, 0.3Vrms
SSA-424 Send: 20 kHz ±200 Hz, 100m Vrms