Onkyo DX-701 CD Player

I own that 20 years old CD Player, it still sounds very good :

At the back of the player you find the RI port (Remote Interactive). It is a 3.5mm mono jack that can be used to connect other Onkyo elements :

For example if you connect an Onkyo amplifier with an IR remote, the amplifier IR remote can control both the amplifier and the player thanks to the Remote Interactive port. In fact you can daisy chain several onkyo elements (Tape player, DVD player, etc.) and control all the elements with a single remote.

This is a very clever idea and today all Onkyo HIFI elements still sport a Remote Interactive port.

Onkyo RI protocol

The LIRC project provides information about the RI protocol :

• http://lirc.sourceforge.net/remotes/onkyo/Remote_Interactive
• http://lirc.sourceforge.net/remotes/onkyo/Remote_Interactive_TX-SR505SE

The files give the pulses encoding under LIRC format is as follows (durations are in µseconds) :

bits            12
flags SPACE_ENC|CONST_LENGTH
eps             30
aeps           100

header        3000  1000
one           1000  2000
zero          1000  1000
ptrail        1000
gap          67000
toggle_bit       0

From there it is very easy to draw the form of the signal. It is space encoded, with a header and a trailer and the message is composed of 12 bits :

Now we know the waveform and the encoding of the Remote Interactive signal, what about the signal level ?

Given the age of the CD Player (and of the RI protocol) the signal is TTL, that is :

• 0 (low) is 0 Volt
• 1 (high) is 5 Volts

For more details about TTL you may refer to Wikipedia

RI Codes for DX-701

The codes for my DX-701 CD Player cover all the functionalities that are accessible on the device facade :

# RI codes for DX-701 CD Player
# RI codes for DX-701 CD Player
CD_Forward               0x0F00
CD_Rewind                0x0F01
CD_Repeat                0x0F06
CD_Clear                 0x0F08
CD_Memory                0x0F09
CD_Display               0x0F0A
CD_Eject                 0x0F0B
CD_8                     0x0F0C
CD_9                     0x0F0D
CD_0                     0x0F0E
CD_Digits                0x0F0F
CD_1                     0x0F10
CD_2                     0x0F11
CD_3                     0x0F12
CD_4                     0x0F13
CD_5                     0x0F18
CD_6                     0x0F19
CD_7                     0x0F1A
CD_Play                  0x0F1B
CD_Stop                  0x0F1C
CD_Next                  0x0F1D
CD_Prev                  0x0F1E
CD_Pause                 0x0F1F
CD_Random                0x0F46

A rather complete list of Remote Interactive commands is given on the LIRC project site.