Now some of these codes do unlock older samsung phones i try the d500 but it never worked for me so i had to use a serial cable but some of these codes shows you hidden menus for the SP lock if its locked to a network or not.

Type this codes in without any sim card in the phone.

*#7465625# - to check the locks....all locks are inactive ...these are all the locks...
network lock - inactive
subset lock - inactive
sp lock - inactive
cp lock - inactive
sim lock - inactive
active lock - inactive
phone lock - inactive
auto network - inactive
auto subset lock - inactive
auto sp lock - inactive
auto cp lock - inactive
auto sim lock - inactive

*#232337# - For your Bluetooth ID

Now these codes below might unlock older samsung's to try yours if you like.

*7465625*638*00000000*00000000#
NEXT ENTER
#7465625*638*00000000#
NEXT ENTER
*#7465625#

Now your locks should be inactive if you get error message's i think i cable solution is needed.