If there are codes for Gem or Jerrold, they may work. I can't remember which company it was but Motorola bought them some time ago and many of the Moto branded boxes were based on them.
When you enter 'codes' into a pre-programmed remote you are entering a setup code. It is just a unique identifier that points to a table in memory that has the details for a particular brand or model of device - which IR protocol it recognizes and at what frequency, and the list of numbers for each device function.
If there are no setup codes that work there is nothing you can do unless the remote can be flashed to add new codes (like the low price One-For-All remotes). That search function just goes through every single setup code in memory and may work sometimes because a lot of devices use the same protocol and codes (function numbers - not setup codes).
