Figure 3: BHX2 Footprint (Top) view
User Interface
Pins Name
TXE
Function
1
Transmitter Enable. Low = ON, Open = RX mode. Internal 10kΩ pull-up to 4V
DC coupled digital data input for 3-12V CMOS logic. Leave open if unused
50mV - 2.5v p-p AC coupled input. Variable gain
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
2
TXD
3
4
5
6
AF in
RSSI
SQF
AF out
RXD
7
8
9
10
11
12
13
+4.4V out Regulated DC supply. 75mA max. drain. Present if unit is powered
0V
Ground
Serial programming/configuration input at RS232 level
PGM
P1
P2
Parallel frequency select inputs. Inverted logic, internal 10kΩ pullups to 4.4V
P3
Notes:
1. BHX2 transmitter section inverts sense of the baseband stream, so a logical inversion is
present between input of TX and output on RX
2. Carrier detect mutes the AF and DATA outputs. It can be disabled by rotating the level set
trimmer fully ACW.
3. There are no pullups on the open collector outputs.
4. The sofware incorporates a 1200baud dumb modem, compatible with that implemented in
TX2M, RX2M, TR2M, SMX2 and UHX2 radios ( i1200 tones and format ).
5. RS232 input pins (10 and 11) tolerate true +/- levels. No buffering is required.
6. This unit actually consists of a TR2C RF board and an AFS2-458 amplifier module,
combined with a 5v LDO
7. In future versions of the software, pin 13 will have a modem handshake function
8. The BHX2 has the same footprint/pinout/function as the TR2M (TR2B), but the case is
longer, and the RF output is a coaxial connector. Compared to an TR2M, the minimum
supply voltage is higher (5.5v vesus 4.5v).
Radiometrix Ltd
BHX2 Data Sheet
page 3
RADIOMETRIX [ RADIOMETRIX LTD ]
