Officially released TI Modules and Peripherals for the TI99/4a are marked with a serial number which indicates the place and date of manufacture.
The serial number may give a limited indication of the version of software contained in the device - TI made continuing changes which have not been documented.
A typical serial number (from a console) is 5081255 LTA3782.
The final digits indicate manufacture in week 37 of 1982.
The letters LTA indicate place of manufacture- some of those used by TI include:
ATA was Abilene, Texas, America ATD (not used for the TI99/4a) was Austin Texas ACH was Almelo, Common Market, Holland. LTA was the main TI99/4a facility, Lubbock in Texas, America. RCI was Rieti, Common Market, Italy.
This format was used on other TI products after 1976