OG_MU4-RS2IF_v10e Circuit Design, Inc.
12
OPERATION GUIDE
The MU4-RS2 is not optimized from the point of view of physical functionality for embedding in final products. When
designing systems that use the RS232C interface, we recommend that you refer to the circuit diagram of the
MU4-RS2 given in this operation guide, and implement the interface part in your user system.
When using the MU4-RS2 without further modification, ground the unit from the MU-4 leg nearest the antenna (the
leg on the soldered side) to the case. Moreover, determine the position and number of grounds through testing.
If you house the product in a case, determine the position of the ground and antenna through a variety of tests.
External LED terminals have been newly added to this product. In addition, if you attach LEDs to the case, connect
them with inch-pitch through holes with reference to the diagram below.
MU-4
RS
2
32
C
c
ab
le
User
PC
Antenna *2
1
2
3
4
5
6
Power LED
Tx LED
Rx LED
GND
+3v
+3v
*1
100pF
100pF
MU4-RS2
100pF
*1: Solder the terminal lug etc. and connect it to the user case
ground. Determine the connection point with various tests.
*2: If the antenna is bent to fit inside, the communication
range falls and communication errors become frequent. Do
Not put the antenna inside a metal case.
*3: Terminal pitches are all in inch sizes.
D-Sub
For external
Powe LED *3
For external
Tx LED *3
For external
Rx LED *3
2
4
1
3
5
6
Connecting external LEDs
.
・
To prevent noise, attach a ceramic
capacitor of about 100 pF to the LED.
・
Terminals 1, 3, and 5 there are 1k
Ω
resistors in the MU4-RS2.
Chapter 4 How to Design a User System
4.1 Embedding the Product
