AES cartridge
A NEO-ZMC2 or PRO-CT0 chip is used to pre-serialize sprite graphics to be output to the cartridge edge. For the PRO-CT0 carts, a NEO-ZMC chip can also be present to multiplex the ADPCM-A and ADPCM-B data accesses to the V ROMs.
This is the main difference with MVS cartridges and is the reason MVS to AES convertors were made.
The cartridge connector has 2*2*50 (200) pins. See pinouts.