Mapping symbols between platforms is one of the most challenging aspects of cross-platform trading. Most platforms rely on a complex table with cryptic symbols to perform this function, and changing contract months can be quite painful.
One obvious solution is to force the trader to always specify the exact, full contract name (e.g. "F.US.EPZ15" for the eMini S&P 500) in their EasyLanguage code but this is certainly not ideal.
Instead, Independent Trader Central leverages the power of the Independent Trader community to simplify this process for its Members. All you need to do is pass a tradable Tradestation symbol to Independent Trader (e.g. @ESZ15.D), typically using the GetSymbolName keyword. ITC will do the rest, attempting to extract the expiration month and year, identify the symbol root, look the symbol root up in the Symbol Root Table, construct a tradable ITC symbol, and register that symbol as a tradable instrument with Instrument Manager. This entire process is transparent to the trader!
When it comes time to roll over futures contracts, the trader need only change the symbol in Tradestation. ITC will automatically identify the change, register the new contract month, and begin using it for new trades. There is no need to edit either code or make changes in a complex or confusing table.
Of course, if you prefer to specify symbols yourself, you are always free to do so. You are also free to make modifications to the ITC Symbol Root Table file as you see fit.
There are many thousands of symbols, so it is unwieldy for any one person to maintain an accurate list. Instead, rather than each Member wasting time defining their own symbol root maps, Independent Trader uses an edit-friendly CSV file, "Independent Trader Symbol Root Table.csv", which can be found in the ITC program directory. This file is curated by the community and contains a large number of symbol mappings with new mappings being added all the time. In most cases, because this file is being maintained by the community you won't need to make any modifications to it (or even think about it at all, for that matter).
In most cases, all you need to do is just use fully qualified, tradable symbols in Tradestation for your charts and ITC will identify the correct symbol for your account.
It is obviously important to test the symbol translation prior to using it to trade live to ensure that the translation is being performed to your specifications.