Figure 3: QPT1 footprint (top view through can)
Pin description (PCB mounted version)
Pin
1
2
Name
Vcc
0V
Function
12V DC supply (11-15V). 550mA typ. current drain
Ground
3
4
TXE
TXD
P3
Transmitter enable. Low = ON, open = off. 100K pullup to (raw Vin -4v)
DC coupled input for 3V CMOS logic. Rin=47kΩ
Parallel Channel select MSB
5
6
7
8
P1
P2
P0
Parallel Channel select
Parallel Channel select
Parallel Channel select (LSB) and serial programming/control input
(inverted logic level RS232)
Ground
9
0V
Notes:
1. No 'modem version' is available, but the PL_ and CX series firmware can be used
2. Parallel port has a 50K pullups to internal 4v rail
3. Caution. The TXD and P0-P3 inputs are not high voltage tolerant. Low voltage logic, or
switches to ground, are required.
4. Overall thermal power dissipation in normal use is around 4 watts, rising to 6-7 watts under
aerial fault conditions.
5. This is a 2 watt output product. Good grounding , good quality aerials, properly mounted,
and a low impedence power supply are required if full performance is to be reliably
obtained. If feasible, we recommend mounting the module, and the board it is on, inside a
metal enclosure, with the RF connctor exiting through a bulkhead. All signal and power
feeds should be filtered and/or decoupled.
Failure to observe these measures can cause modulation distortion ('recirculation' effects)
or instability. Also be aware of the effect that the strong RF fields generated by this device
(and it's aerial) can have upon other adjacent circuitry if this is not properly screened,
filtered or otherwise protected. Regulators, sensitive analogue circuitry, and
microprocessors seem especially interference prone.
6. Two watts of RF at VHF can cause an unpleasant and painful burn. Be careful
7. This design uses the LMT1 100mW transmitter as an internal component
Radiometrix Ltd
QPT1 Data Sheet
page 3
RADIOMETRIX [ RADIOMETRIX LTD ]
