Most of the newer Pioneer laserdisc players have an odd 15-pin connector in back. Cables that fit this 15-pin connector are rare and, as far as I know, can only be purchased from Pioneer directly! The cable you want depends on what type of serial port you have on the back of your computer. If you have a 25-pin serial port (older computers) you will want part # CC-03. If you have a 9-pin serial port, you will want part # CC-13. Mentioning the part # to the person you talk to at Pioneer will likely help a great deal since they will probably have no clue what you are talking about otherwise =]. If you know what you're doing, you can also make your own cable.
You also need to set the dip switches in the back of your player. Some Pioneers operate at 9600 baud (preferred), others only operate at 4800. DAPHNE can handle both. There is usually a diagram on the back of your player that shows how to set the dip switches properly.
Pioneer's Phone Number 1-800-421-1606
Amazingly, Pioneer still has documentation online for several of their late-model laserdisc players: http://www.pioneerelectronics.com/pe/links/list/0,,2076_4253,00.html
And here's the pin-out if you want to make your own cable.
Player (15 pin) Computer (25-pin) (1) GND <--> (7) GND (2) TXD ---> (3) RXD (3) RXD <--- (2) TXD (4) DTR ---> (5) CTS
Player (15 pin) Computer (9-pin) (1) GND <--> (5) GND (2) TXD ---> (2) RXD (3) RXD <--- (3) TXD (4) DTR ---> (8) CTS
The 15-pin connector is the same style that fits a PC game port, and the AUI (thick Ethernet) port on old-skool network cards. (This may help in tracking down approprate connectors/cables to adapt.)