User's Manual

Radio Activity S.r.l. 25 / 44
ALR_OUT : [OUT] it is open from GND when the equipment detects an alarm condition. Power off is an alarm
condition.
FAN : [OUT] it is closed to GND when the temperature of the internal RF power amplifier rises above the
threshold (typ 65°C). It can be used to switch on cooling fans in a cabinet.
PTT_OUT_conn : [OUT] it is closed to GND when the transmitter goes on air. It is possible to insert a pre-time
to allow the right switching on time to an external RF power amplifier.
PPS_IN_CONN : [IN/OUT] this pin supports an external PPS signal or can share the internal PPS (from GPS
receiver or from the PTP or from other sourced synch). As described previously, a bus connection between
different co-located KAIROS realizes a multiple GPS reception with automatic backup. This pin can also be
configured to accept an external synchronous clock or an external pulse per second signal. Contact Factory
for further details.
IN/OUT_1+1_MNG_CONN : [IN/OUT] these pins support a simple protocol to allow two KAIROS to
functioning as 1+1 (main and spare) equipment.
V_ext_1 : [IN analog] not isolated inputs for voltage sensing (10KOhm / 0..24V referred to ground); the value
of this voltage can be seen via the remote control tool.
+12Vcc_TO_EXT : [OUT aux supply] this pin provides 13.2V, limited at 400mA, to supply a general purpose
external device
3.3.5.2 Audio I/O
KAIROS provides two 2/4 wires + E&M balanced interface for external audio devices like consoles or phone
lines. These audio ports carry analog or DMR communications (in this case the AMBE codec option is
requested).
The inputs are IN_1A/IN_1B for the Audio Line 1 and IN_2A/IN_2B for the Audio Line 2 (Z_in = 20KOhm
differential / 10KOhm single ended). The outputs are OUT_1A/ OUT_1B for the Audio Line 1 and OUT_2A/
OUT_2B for the Audio Line 2. These two outputs have different impedance:
∞ Audio Line 1 Z_out = 600 Ohm differential / 300 Ohm single ended.
∞ Audio Line 2 Z_out = 150 Ohm differential / 75 Ohm single ended.
These IN/OUT ports are balanced and ground referred (NOT FLOAT! don’t apply to these pins more than
20Vdc). For long line use, it is recommended to insert an external 1:1 transformer in order to isolate the port
from static voltage difference that can be arise between the line ends.
They can be used as balanced (suggested method) or as single ended using only one of the IN/OUT pin. The
nominal level of the audio signal in/out is -10dBm and can be regulated via setup tool between -20 and 0
dBm (-14 to -6dBm in single ended).
These Audio ports, in conjunction with the E_1, E_2, M_1, M_2 I/O signals described before, realize a double
4Wire+E&M interface.
In analog communications the standard settings of these ports are: