RS-X is easyIPC over RS485 using a special 4-wire cable and a timing protocol. Several modules are designed to be connected to a RS-X network as well as a series of infrastructure components needed to build an automation/robotic network based on easyIPC.
easyIPC is about providing a plug & play network with open, secure communication to enable more complex robotic/automation systems. The network focus on using Raspberry PI as intelligent nodes.
CAN-X and RS-X technologies are very similar from a functional perspective, and also from a wire perspective. The main difference is that RS-X is based on RS485 using UART/USART that is available on all devices, while CAN-X is based on CAN ports that are a more limited resource.
CAN uses an arbitration principle that makes it easy to implement multi-master communication, but it limited by a small 8 byte payload. Arbitration will however secure close to 100% utilization of a network.
RS485 in classic mode is more flexible and available than CAN, also more easy to get working as the arbitration timing can be a bit tricky. The drawback is that the wiring have no support for multi-master networks.
The RS-X protocol uses a chain reaction scheme where each device send an EOT (End of Transmission) allowing the next device to start. This enables a timed multi-master where each device can communicate within a small time-frame that is adapted to standard UART/USART features.
Both Technologies have their ups and downs, but availability of RS-X and the fact that RS485 is easier to get working account for a lot on the smaller micro devices. Both RS-X and CAN-X are available and can be used together as part of a easyIPC network. In fact, it will be fully possible to have a wire that starts as RS-X and ends as CAN-X or wise versa.