Turn on the unit to be controlled manually. Press and hold Setup until the voice prompt starts the programming menu. Press 1 to directly enter a code. Press 2 to search for a code. Note at any step if the no buttons are pressed for 15 seconds, the remote will enter the usage mode. Start again from the Setup button. When prompted, press the device button for the device you want the remote to control.
Then enter the 4 digit code (if using the direct programming mode). The LED will blink twice and the remote will announce success. Test if the remote works (play, power) when prompted to test the code and press Setup if it is successful. Then wait until the remote says goodbye and then press Power again. The unit should turn off. (I strongly suggest testing other functions as well after this.) Repeat with other codes if unsuccessful.
For searching through the programmed codes, start as indicated above: press and hold Setup and then press 2. When prompted press the device button. Then press the test key (power usually). Slowly alternate pressing CH+ and power until the device turns off. Press CH- if you miss the device turning off. Press Setup to store the code. Then after the remote says goodbye check if the remote works for all the functions. Repeat the above if it doesn't work for all features.
The manual for the remote is available here: http://files.remotecentral.com/view/852-1041-1/radio_shack_15-2146_6-in-1_easy_setup_voice.html
. This file is a PDF in a zip archive and does include the code list at the end.
Please note that codes in the remotes are limited to those for devices released at least 6 months before the remote was programmed. If your device is newer than your remote, you may need a new universal remote. I suspect this remote may be from 2004.
I hope this helps.