 
 
|  | TI-92+: I2C | A case study on how to implement an I2C (software!) interface for the TI-92x (and may be TI-89, too). No interface required! | 
|---|---|---|
|  | HP48/50: E248 | A kind of a best match E12/24/48/99 resistance ratio calculator. RPL. | 
|  | Dummy | As the name implies, just a placeholder... | 
|  | PC-1500: 3s | A 3s (stupid, simple, slow) interface for Sharp PC-1500. Basic controlled. | 
|  | PC-1500/1600: stuff | I still use them, sometimes. |