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File name Building a Serial Interface for JP1.2 and JP1.3.pdf

BUILDING A SERIAL INTERFACE FOR JP1.2 AND JP1.3 (FLASH) REMOTES Tommy N. Tyler Revised 10 February 2009 All previous construction articles and trouble-shooting guides for serial JP1.2/3 (flash) interfaces should be considered obsolete because they were written when the terminology "JP1.x" was still in use, where "x" was "1", "2", or "3" depending on the type of flash processor used in a remote. Model JP1.1 remotes never became popular, and once we learned that interfaces for them were incompatible with the newer and more popular JP1.3, we discontinued support for JP1.1. The only type of flash processor remotes in current use are JP1.2 and JP1.3, and interfaces that work with both of these should be referred to as JP1.2/3 (flash) interfaces rather than JP1.x interfaces. Information on JP1.1 Interfaces can be found at http://www.hifi-remote.com/forums/dload.php?action=file&file_id=6013. Here are the latest preferred schematics for serial interfaces that work with any JP1.2 or JP1.3 flash remotes. Either version can be used with USB-to-Serial converters. They DO NOT work with old obsolete JP1.1 remotes, nor with JP1 (EEPROM) remotes. Sorry, there are no instructions available at the present time for construction. If you build one, you can find test and troubleshooting instructions at http://www.hifi-remote.com/forums/dload.php?action=file&file_id=5964. Figure 1. Discrete Transistor Version of Serial JP1.2/3 (Flash) Interface CORRECTION DATED JUNE 26, 2009 The resistor connected between JP1 pin 6 and the base of transistor Q3 is erroneously labeled R3 and should be R6. Also, the value of this resistor should be increased from 4.7K to 100K to prevent Q3 from being partially turned on. The symptoms of this problem are that 2-battery remotes (such as URC-8820) are immediately disabled any time they are connected to the interface, and must be unplugged in order to use them. The resistance value does not prevent upload and download. -- page 1 of 2 pages -- Figure 2. IC Version of Serial JP1.2/3 (Flash) Interface -- page 2 of 2 pages --