Buy one (7 on sale)
Initially sold for ¥15,000
The Yamaha RAM1 or just "data RAM" is a cartridge to be used to store voices from the Yamaha DX7. It's visually identical to the ROM cartridge but holds just one bank in memory (32 sounds), as such it was considered to be of poor value considering the high cost and the availability of third party solutions.
It can be used on post-1986 Yamaha products via the use of the ADP1 cartridge adapter.