Pioneer DRM-604X - Manual (Page 42)

Using CD Player (CDP) commands to control the drive
After installing the proper device driver, the /C:CDP switch should be found in the
Device line of the CONFIG.SYS. When this switch is present, CD Player
commands can be sent the player either from the DOS Prompt or by using the
MPC utility as described in Chapter 3 for IBM-PC and compatible computers.
For example, when sending commands from the DOS prompt:
C:\>ECHO 1KL >CDP Turns on the Key Lock (disables eject button).
C:\>ECHO 0KL >CDP Turns off the Key Lock (enables eject button).
See Appendix D for a list of CDP Commands. These commands can be used after
the ECHO statement in the lines described above.
Chapter 5 Special Issues
Owner’s Manual / Software Driver Installation Guide 5-3