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Nice video.....really would have been nicer to see this BEFORE I installed SC-2s to run my Fastrack switches. What I do not understand is why my Legacy runs the SC-2s and Fastrack switches so much better than the TMCC Cab1. What Mike does not explain is the lack of being able to attach too many devices to the serial port on the Legacy.
Answers anyone?
Jeff, my research indicates that there are 3 types of serial-port accessories, and they draw different amounts of current:
1. The ZStuff Data Wire Driver - These can have different values of resistors. I have not had a unit to test, and I don't feel comfortable quoting numbers based upon "typical values" on semiconductor data sheets. The current may be as high as 10 mA.
2. The TPC300/400, which has an optocoupler on the data input. They require about 1.5 mA each. Legacy can drive about 4 or 5 TPCs if there isn't a Data Wire Driver on the system.
3. Other devices like the ASC that have high-impedance data inputs. You could drive several of these without problems.
The Legacy Base can source about 7-8 mA before the output voltage drops too low.
My MANCO Booster for the serial port provides about 10 times as much current as the Legacy Base output. See http://www.trainfacts.com/trainfacts/?p=406 for details. For systems with group 1 and 2 accessories above, this can solve any problems.
Dale is correct and right now the only solution is Dale's product.
Jon Z has told us via the LUG meeting notes that Lionel expects to have something to address the issue this fall.
From the LUG Notes... Jon Z's answers in RED
Will Lionel be introducing new serial devices in the future or is the strategy to replace the current devices with wireless devices like the SC-2?
>> We need to upgrade the Serial infrastructure to Legacy compliance. The Serial drive levels have been a topic of discussion; and with the Legacy infrastructure upgrade, this concern would be banished. We have a plan to resolve the drive levels this year, and make the infrastructure available with not only improved drive levels, but functionality enhancements. These enhancements will support all of the newer serial related functionality, such as the IR transmission receiver track.
