Am I responding to this question twice? I'm sorry if I have already answered this, but it seems the system has duplicated your post.
You'll need the lock code for your radio. Honda uses a security code on their radios which would deter a thief from stealing it. Sometimes you can find the radio code in your owner's manual. There is a card that the dealer is supposed to write the code on and then the original owner is supposed to tear the card out and keep it in a secure location.
Chances are that card is long gone. Some honda dealerships mark the radio code elsewhere on the vehicle for convenience to the customer. One honda dealer in my town writes in in permanent marker on the fuse box cover. Another puts a small white sticker on the side of the glove box with the radio code.
If you can't find the code anywhere you will probably have to call the dealer and give them your vin, or the serial number off of the back of the radio. They should be able to look up your code in a honda-only database.
Here is a way to get the serial number from the radio without pulling the radio out and looking at the sticker on the back. This is the number you will provide the dealer and they will give you your un-lock code.
1. Turn on the radio, and turn on the ignition switch to the ON position. Verify the radio display indicates CODE.
2. Turn off the radio and press and hold #1 and then #6 radio preset buttons and while holding the buttons turn on the radio. The radio will display a U and 4 digits and then an "L" and 4 digits. The first 4 digits of the serial number are with the "U" the last 4 digits of the serial number are after the "L". For example if it reads "U" 1234 and "L" 4321, the serial number would be 12344321. Call the dealer with that number and they can get the 5 digit radio code for you.
I do not expect you to rate me twice, I just want to make sure you get your question answered.