What is an extender?

[rxchng]

Could someone please kindly tell me what exactly is an "Extender"? I read Don Grovestine's "What and Why of JP1" from cover to cover, even though it contains an Extender section, I found no definition of it.

Is Extender a piece of software used to enhance the remote features? If so, is an Extender stored in the EEPROM?

[johnsfine]

Is Extender a piece of software used to enhance the remote features? If so, is an Extender stored in the EEPROM?

Yes and Yes and http://groups.yahoo.com/group/jp1/files/Extenders/

[rxchng]

For some reason, my company blocked access to the yahoo group site. So I can't access any of the files from work. I will try read some more from Yahoo tonight. Thanks for a speedy reply, Johns Fine. I have read your name many times here and there. Are you the IR expert?

My next question is why only some remotes are Extender-Compatible but not all if it's just a piece of software stored in EEPROM...?

[johnsfine]

My next question is why only some remotes are Extender-Compatible but not all if it's just a piece of software stored in EEPROM...?

EEPROMs are VERY small (from the point of view of storing software). So an extender couldn't possibly take a direct approach to doing the things that it does. A direct approach would be a piece of software far larger than the whole EEPROM size. The extender must fit in EEPROM with most of the EEPROM left for upgrades, KeyMoves and Macros.

The extender must trick the programming that's built into the remote into doing the job that the extender wants done (much the same way a computer virus tricks some bloated piece of MS crap into doing what it wants done). That process must be finely tuned to the specific program being tricked (the same way a Virus aimed at IE won't do anything to my copy of Mozilla).

An extender is even smaller than a typical virus, so there is less room to make it adjust across versions of the target program (the way some IE viruses can adjust across a few versions of IE).

[The Robman]

Just to add to what John said, the bottom line is this: each extender has to be hand written to work with a particular remote. So in truth, almost every remote is Extender-Compatible, it's just that nobody's written an extender for the ones listed as not being Extender-Compatible.