Revision 1.0 Page 12 of 25
User Guide
Figure 9. PC output interface

3.2.2 Jumpers

The application board can be set up to interface a headset microphone and loudspeaker, or a PC audio
outlet by placing the jumpers as shown in Table 3. ”Audio filter settings” below. The filter components
mounted shou ld be appropriate for most headset loudspeakers.
Table 3. Audio filter settings

3.2.3 Antenna

The RF output of the radio modu le is matched to approximately 50 o hm. An antenna mu st be connecte d to
the SMA connector to set up an RF link.

3.2.4 Power supply

The application board is fitted with two coin-cell battery holders, connected in series, for use with ZinkAir
(type 675) batteries. The board also contains a footprint for a CR2 Li battery holder (1/2 AA, Bulgin
BX0031). Alternatively, an external power supply can be connected to P3. You select battery or external
voltage with SW6.
The voltage supply to the RF module should be between 1.9 and 3.6 V. If the onboard 2.5 V linear regula-
tor is used, the input voltage should be between 3 and 15 V. The linear regulator can be switched on or
bypassed with SW7 and SW8 (both switches should have the same position).
Note: Do not exceed 3.6 V when using external volt age unless the linear regulator is used, as this
can damage th e ra dio modu le.
CJ2 CJ3 W1 W2
Connecting to
headset Co nnect to headset
microphone. Connect to headset
loudspeaker Mount jumpers 4
and 5 Mount jumper 2.
Connecting to PC Connect to PC micro-
phone input Connect to PC loud-
speaker output Mount jumpers 1,
2 and 3 Mount jumper 1.
R1
1k
R2
47
C1
2.2u
C2
2.2u
PC loudspeaker out AIN