Radiometrix Ltd

TX1M/RX1M Data Sheet

page 9

Application circuits

RSSI (C1)

SQF (C2)

AF out (C3)

RXD (C4)

+4.4V out (C5)

GND (C6)

(C7)

P1 (C8)

P2 (C9)

P3 (C10)

PGM

CD

1

2

3

TXD

SGD

4

6

7

8

9

5

Data out

ADC or A meter

µ

+4.4V

Parallel

Channel

Select

100nF

4.5 - 15V

Antenna

0V (C1)

TXD (C3)

AF in (C4)

+4.4V out (C5)

PGM (C6)

(C7)

P1 (C8)

P2 (C9)

P3 (C10)

TXE (C2)

GND

1k

Ω

TX

2

3

TXD

SGD

4

6

7

8

9

5

Transmit Enable

Parallel

Channel

Select

4.5 - 15V

Antenna

Figure 6: Test circuit of TX1M and RX1M

TX1M/RX1M can be configured using any PC/Laptop/PDA having a serial port and modem/terminal

program. TXD (pin 3) of DB9M connector can be directly wired to PGM (pin C7) of the TX1M/RX1M and

SGN (pin 5) of DB9M connector should be connected to common ground pins.

The whole frequency/channel table is user reconfigurable to 128 channels within 2MHz band of

supplied frequency subject to regulatory band limits.

0V (C1)

SQF (C2)

AF out (C3)

RXD (C4)

+4.4V out (C5)

GND (C6)

(C7)

P1 (C8)

P2 (C9)

P3 (C10)

PGM

CD

1

2

3

TXD

SGD

4

6

7

8

9

5

PC serial port

Data In

ADC

VDD

Parallel

Channel

Select

100nF

4.5 - 15V

Antenna

0V (C1)

TXD (C3)

AF in (C4)

+4.4V out (C5)

PGM (C6)

(C7)

P1 (C8)

P2 (C9)

P3 (C10)

TXE (C2)

GND

1k

Ω

TX

1

2

3

TXD

SGD

4

6

7

8

9

5

PC serial port

Transmit Enable

Data Out

Parallel

Channel

Select

4.5 - 16V

Antenna

Figure 7: TX1M and RX1M interfaced to host microcontroller and serial port for configuration

TX1M and RX1M can be directly interfaced to a host microcontroller which can generally be powered by

the regulated +4.4V output on pin 5. Three I/O pins on the microcontroller port can be assigned to select

the first 8 channels on frequency table of the appropriate band for which the module is configured by

pulling the P1-P3 pins low. Channel select pins of TX1M and RX1M have internal pull-up to 4V supply

rail, hence channel selection operate on inverted logic.

Digital Received Data Output (RXD) pin on the RX1M is an open collector output, which should be

pulled-up to required voltage swing level (e.g. +4.4V or Vcc).

RX1M has an automatic noise squelching function which is activated when there is not any RF signal at

detectable level on the channel or if the non-coherent noise like interference level is high enough to

block any weak RF signal from being received. SQF is provided as an open-collector output for

monitoring which should be pulled-up to required voltage swing level. SQF output will jump to pull-up

voltage level if received RF signal level at the RF In/Out pin of the module is about 3dB below the level

required to produce 12dB SINAD level on demodulated AF Output signal. SQF pin can be connected to

an LED to act as a Carrier Detect indicator. Pull-up resistor value should be reduced (e.g. 1k

Ω)

according to the current requirement to produce satisfactory brightness on the LED used.