| Circuit # | Function |
| 1 | Generally Not Used (+5v @ 50 ma) |
| 2 | Transmit Line |
| 3 | Receive Line |
| 4 | DTR (Data Terminal Ready) |
| 5 | CTS (Clear to Send) |
| 6 | Not Used |
| 7 | +12v (Used if charged via cable) |
| 8 | Charger Ground |
| 9 | Digital Ground |
| 10 | Generally Not Used (-5v @ 50 ma) |
A minimum wiring for 'send only' communication (IBM) is as follows:
| X-Rite (10c/RJ45) | IBM 9Pin (DB9p) | IBM 25Pin (DB25p) |
| 2 X'mit data | 2 Rec'd data | 3 Rec'd data |
| 9 Digi Ground | 5 Digi ground | 7 Digi ground |
Many devices will require some kind of hardwire handshaking. All instruments provide a +8 volt signal on line 4 ( our DTR ) which can be connected to the receiver's hardwire handshake line ( usually CTS ). Our DTR is dropped during power-up and while taking measurements to inform the receiver that we are not ready to accept data. Similarly each unit can monitor its line 5 ( our CTS ) to see if the receiver is ready to accept data. Should you need the additional wiring a more complete schematic follows:
| X-Rite (10c/RJ45) | IBM 9Pin (DB9p) | IBM 25Pin (DB25p) |
| 2 X'mit data | 2 Rec'd data | 3 Rec'd data |
| 4 DTR handshake | 6 DSR | 5 CTS |
| 5 CTS/Busy handshake | 7 RTS | 20 DTR |
| 9 Digi Ground | 5 Digi ground | 7 Digi ground |
If two way communication is desired then one more wire may be added; i.e.:
| X-Rite (10c/RJ45) | IBM 9Pin (DB9p) | IBM 25Pin (DB25p) |
| 2 X'mit data | 2 Rec'd data | 3 Rec'd data |
| 3 Rec'd data | 3 X'mit data | 2 X'mit data |
| 4 DTR handshake | 6 DSR | 5 CTS |
| 5 CTS/Busy handshake | 7 RTS | 20 DTR |
| 9 Digi Ground | 5 Digi ground | 7 Digi ground |
If Pin5 is turned off (instrument I/O configuration), the instrument will not monitor the handshake line from the computer / printer / etc. With most printers this will result in data overflow. With most computers this handshake is not required.
| X-Rite (10c/RJ45) | Macintosh (8pin/DIN) |
| 2 X'mit data | 5 RxD- Receive data (minus) |
| 3 Rec'd data | 3 TxD- Transmit data (minus) |
| 4 DTR Handshake Out | 2 HSKi/Clock Handshake In |
| 5 CTS Handshake In | 1 HSKo Handshake Out |
| 8 Charger Ground | 8 RxD+ Receive data (plus) |
| 9 Digi Ground | 4 Digi ground |
The above description is electrically equivalent to X-Rite's PN SE108-79 interface cable.