| Name | Description |
|---|---|
| Standardised electrical current between 0 mA and 20 mA for information transmission. | |
| Standardised electrical current between 0 mA and 20 mA for information transmission. | |
| Standardised electrical current between 4 mA and 20 mA for information transmission. | |
| Standardised electrical current between 4 mA and 20 mA for information transmission. |