Figure 3: SFX2 Footprint (Top) view
Pin Description - SFX2
Pins
A1
A2
Name
Vcc
GND
Function
6V - 15V
Ground
B1
B2
B3
RF GND
RF
RF GND
RF ground
To the antenna
RF ground
C1
C2
C3
C4
C5
C6
C7
C8
TXE
TXD
AF in
RSSI
SQF
AF out
RXD
+5V out
0V
Transmitter Enable. Low = ON, Open = RX mode. Internal 10k pull-up to 5V
DC coupled digital data input for 3-12V CMOS logic. Leave open if unused
50mV-2.5Vpk-pk AC coupled variable gain input. Factory set to 1Vpk-pk
DC level between 0.5V and 2.5V. 60dB dynamic range
Noise operated carrier detect. Open collector. ON/low = no signal
200mVpk-pk audio. DC coupled, approx 1V bias. Muted by squelch
Open collector output of data slicer suitable for Biphase codes
Regulated DC supply. 100mA max. drain. Present if unit is powered
Ground
C9
C10
C11
C12
C13
PGM
P1
P2
Serial programming/configuration input at RS232 level
Parallel frequency select inputs. Inverted logic, internal 50k pullups to 5V
P3
Notes:
1. By changing specific links and components, either the rx and/or the tx path can be made to invert the
sense of the baseband waveform, or not. Standard issue SFX2 inverts on both tx and rx paths (so is
equivalent to a TR2I-458-5)
2. Carrier detect mutes the AF and DATA outputs. It can be disabled by either rotating the level set
trimmer fully ACW (disabling both) or by removing the solder link (which disables only the AF mute).
The carrier detect is relatively slow (approx 25mS) so is not compatible with the full sub 10mS tx/rx
switching speed capability of the unit
3. There is no pullup on the SQF open collector output. RXD has 47K to internal 5v
4. Unlike the parent TR2M, the SFX2 does not incorporate an i1200 modem
5. RS232 input (pin 10) tolerates true +/- levels. No buffering is required.
Radiometrix Ltd
SFX2 Data Sheet
page 3
RADIOMETRIX [ RADIOMETRIX LTD ]
