The multi-channel serial I/O modules are used in I/O systems of the I-87K series. They have an RS-485 interface and, like the related I-7000 modules, can be controlled via DCON, a simple ASCII protocol. All analogue inputs are isolated from the system bus up to 3,000 V. Isolated digital inputs provide 3,750 V isolation. The I/O modules are available in high profile or low profile versions, depending on the form factor of the I/O system.