Figure 3: SHX1 footprint (Top) view
Pin Description
Pins
RF
Normal mode
Modem mode
1A
2A
3A
NO PIN
RF in/out
RF Gnd
To the antenna
RF ground
4A
5A
6A
User
1
GND
0V
GND
VCCTX
0V
+5V regulated supply for TX 7
TXD
TXE
DC coupled input for TTL / CMOS logic
Transmit enable.
Low = TX mode
NC
NC
2
3
GND
Vcc
P3
0V
4
DC supply input (+5V regulated) 8
Parallel channel select
Parallel channel select
5
BUSY
6
P2
MOD TXD
MOD RXD
PGM in
7
P1
Parallel channel select
8
PGM in
RSSI
RXD
AF out
Serial programming/control input (inverted logic level RS232)
DC level between 0.5V and 2.5V. 60dB dynamic range
Open collector output of data slicer. 47K pullup to 4V
500mV p-p audio. DC coupled, approx 0.8V bias
9
10
11
NC
NC
NOTES:
1. No inversion occurs between TXD and RXD. However, AF out is inverted relative to TXD.
2. PGM, P0 - P3 (parallel channel selects) and TXE are active LOW and have internal 47K pullups to
4v.
3. Open collector output RXD has a 47K pullup to 4V.
4. The software incorporates a 1200baud dumb modem, compatible with that implemented in other
Radiometrix narrowband units ( i1200 tones and format ). Modem operation is selected by a serial
command.
5. Main serial port (PGM) operates at 2400 baud. (Command set is the same as SMX (USA) version).
The unit is capable of operating in 'basic' parallel channel select only mode, or in serial controlled
'expanded' mode.
6. If analogue transmit modulation is needed, then connect a series 1uF cap + 500K trimmer (a
multiturn is advised) in the 'baseband TXD' circuit. Adjust trimmer for 90% of peak deviation (+/-
2.7kHz) at mean input level.
7. The high current (280mA max.) transmitter supply (5v regulated) is fed to a separate pin, on the RF
out connector (pin 6A).
The Vcc (pin 4 on the user connector) can tolerate 4.1 - 15v, and draws up to 25mA. Both pins must
be supplied at all times (most users connect them to a common +5v supply)
Radiometrix Ltd
SHX1 Data Sheet (preliminary)
page 3
RADIOMETRIX [ RADIOMETRIX LTD ]
