| Function | Opcode | Description | Since |
| Cauxin() | 3 (0x03) | Waits for the next available data byte from GemDOS handle 2 (normally device 'aux:') and when available, returns it in the low byte of the returned WORD. | GemDOS 0.11 |
| Cauxis() | 18 (0x12) | Indicates whether GemDOS handle 2 (normally device 'aux:') has at least one character waiting. | GemDOS 0.11 |
| Cauxos() | 19 (0x13) | Indicated whether GemDOS handle 2 (normally device 'aux:') is ready to receive characters. | GemDOS 0.11 |
| Cauxout() | 4 (0x04) | Outputs a character to GemDOS handle 2, normally the 'aux:' device. | GemDOS 0.11 |
| Cconin() | 1 (0x01) | Reads a character (waiting until one is available) from GemDOS handle 0 (normally 'con:'). | GemDOS 0.11 |
| Cconis() | 11 (0x0B) | Verifies that a character is waiting to be read from GemDOS handle 0 (normally 'con:'). | GemDOS 0.11 |
| Cconos() | 16 (0x10) | Checks to see whether a character may be output to GemDOS handle 1 (normally 'con:'). | GemDOS 0.11 |
| Cconout() | 2 (0x02) | Outputs one character via GemDOS handle 1 (normally 'con:'). | GemDOS 0.11 |
| Cconrs() | 10 (0x0A) | Reads a string from the standard input stream (GemDOS handle 0) and echoes it to the standard output stream (GemDOS handle 1). | GemDOS 0.11 |
| Cconws() | 9 (0x09) | Writes a string to GemDOS handle 1 (normally 'con:'). | GemDOS 0.11 |
| Cnecin() | 8 (0x08) | Is the same as Cconin(), except that the character fetched from the input stream is not echoed. | GemDOS 0.11 |
| Cprnos() | 17 (0x11) | Returns the status of GemDOS handle 3 (normally 'prn:'). | GemDOS 0.11 |
| Cprnout() | 5 (0x05) | Sends one character to GemDOS handle 3 (normally 'prn:'). | GemDOS 0.11 |
| Crawcin() | 7 (0x07) | Is similar to Cconout(), however it does not process any special keys and does not echo the inputted character. | GemDOS 0.11 |
| Crawio() | 6 (0x06) | Combines console input and output in one function. | GemDOS 0.11 |