PUMA T2
Technical Handbook
Technical description
Page 38 OTE Proprietary information
P/N: 779-0306/01
Revision 03
Interface signals description:
SERVICE: Digital signal to activate muting (“squelch”) on possible external
loudspeaker.
Coding: SERVICE = GND/Floating ==> External loudspeaker active/mute; open
collector type output.
AP-EXT: Analogue audio signal for single-ended driving of optional external
loudspeaker connected to the external lateral connector, with electrical level
included between GND and VBI.
PTT-EXT: Digital signal for external Push To Talk control.
Coding : PTT-EXT = GND/Floating ==> Push To Talk control active/inactive.
ANT- EST: Digital signal to indicate the presence of an external antenna.
Coding: ANT-EST = GND/Floating ==> External antenna present/absent.
TXD, RXDD: Transmission and reception digital signals, respectively, of the
asynchronous serial line for the connection to external data terminal. TTL 3.3 V
electrical levels (translation to the RS232 standard or other standard electrical
levels is carried out by an adapter circuit placed between the TETRA terminal and
the data terminal). The RS232 standard is programmable, with 1 start, 7 or 8 data
bits, possibly 1 parity check bit and 1 or 2 stop bits; the baud rates that can be
used directly by microprocessor are 110, 300, 600, 1200, 2400, 4800, 9600,
14400, 19200, 28800, 57600. Furthermore, the 38400 and 115200 rates may be
used with suitable programming of the Field Programmable Gate Array (FPGA),
which supplies the microprocessor with an additional clock.
AVVISO: CMOS digital signal to activate an indicator light on an external
accessory when a pending call is received.
Coding: AVVISO = 0/1 == > De-activated/activated signal.
The line is also used as the output of a serial line with CTS/RTS protocol, and
comprises a single hardware control line.
In order to have a CTS/RTS protocol with two control lines it must be reconfigured
as the input and the signal SERVICE as the output.
ENBFOUT: Digital signal for audio amplifier activation on the external vehicular
set.
Coding: ENBFOUT = GND/Floating == > Booster activated/de-activated. It is an
open collector type control, with external pull-up.
P-AUX: Analogue line for auxiliary signals, with electrical level between 0 and +3.3
V. Such level, quantified and codified by the µC for discrete intervals, indicates
particular terminal operational status to the application.
When this line is linked with GND and the equipment is switched ON, an
appropriate circuit selects the bootstrap from the internal ROM.
VBI: Interrupted battery voltage at 7.2/7.4 V nominal. Carries the battery power
supply from the RT board towards optional external accessories downstream from
the switch. The line is protected with a 47 Ohm series resistance. It also allows the
power supply for the red and the green led.
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