The SELDEC-4 CCIR Selcall Decoder is housed in a ‘clear’ plastic case 130mm x 70mm x 45mm with connectors for Power, Audio Input, and Serial Output.

The decoder is designed for either a line input or the onboard electret microphone can be used.

The standard model decoder has a serial output which outputs the decoded data as a 16 digit string with a CR & LF on the end.

If the decoded string is shorter than 16 digits, the string has ‘spaces’ used to make up the 16 digits.

Please note that the SELDEC-4 will only decode selcalls with a length of 5 to 16 digits.

The serial data format used is: 9600 Baud, 8 Data Bits, 1 Stop Bit, No Parity

No Handshaking is used.

There is also a model available with an LCD 2 line 16 character display which also has the serial output.

The unit requires 9 Volts DC at 200 mA. (A suitable plugpack is supplied)

(A 9 Volt battery may be used if wanted for portable applications)

The unit also has LED’s for both ‘Audio Level’ and ‘Data Decode’.

There is also a switch to enable ‘Beep On Decode’ on the decoder.

The selcall tones are decoded according to the following table:

1981 Hz = 0

1124 Hz = 1

1197 Hz = 2

1275 Hz = 3

1358 Hz = 4

1446 Hz = 5

1540 Hz = 6

1640 Hz = 7

1747 Hz = 8

1860 Hz = 9

2400 Hz = A

  930 Hz = B

2247 Hz = C

  991 Hz = D

2110 Hz = Repeat +

1055 Hz = F

+ Note the repeat tone is used when 2 sequential digits are to be the same character…. The firmware decodes these and inserts the correct repeated character.