The TMS6125 is a smaller, 32Kib (4KiB) version of effectively the same chip, with some minor changes to the 'address load' command format to reflect its smaller size.
Texas Instruments calls both of these serial roms (TMS6100 and TMS6125) "VSM"s (Voice Synthesis Memory) on their datasheets and literature, and they will be referred to as such for the rest of this article [REF].