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PT2248 V2.7

- 7 -

June, 2005

Infrared Remote Control Transmitter

PT2248

The PT2248 Code Bits Connection Table for PT 2249A / PT 2250A Series Application is given below:

Rx

PT2248 Code Pin

PT2249A

PT2250A

T1 (C1 Code)

Diode

C1

T2 (C2 Code)

C2

C2

T3 (C3 Code)

C3

Diode

Note: where C1, C2, C3 will be “1” if one diode is connected between CODE and Tn pins; n=1 to 3 in

PT2248; otherwise, it will be set to “0”.

Note: When communicating with any of the PT2249A Series Receivers, C1 Code Bit Data is not used.

Therefore, it is necessary to connect diodes to the Code terminal corresponding to C1 Code Bit

of PT2248. (In this way, the C1 Code Bit of PT2248 transmits “1”. Likewise, when

communicating with any of the PT2250A Series Receivers, C3 Code Bit is not used. Therefore,

it is necessary to connect diodes to the Code Terminal corresponding to the C3 Code Bit of

PT2248.)

TRANSMITTING WAVEFORM

48 a

a

3a

Co de Bi t

Continuous /

S ingl e- Sh ot Code

K ey Input Code

The diagram above shows the basic transmitting waveform. A basic transmitting waveform consists of

12-bits serial data.

The time of bit “a” is dependent on the oscillation frequency (fosc) and is given by the following formula:

a =

fosc

1

x 192