We have an aftermarket cruise control installed (in Suzuki Swift), which is connected to the OBD-II connector to access the CAN bus (according to the installation manual, it uses just CAN-L and CAN-H pins from the connector).
Now I have bought an OBD-II Bluetooth module. Could it be used at the same time as the cruise control?
If I understand the Wikipedia page on CAN bus properly, devices are connected to the bus parallel and terminator resistors are only at the two ends of the bus line. So it should be possible to have both devices connected to the OBDII connector... About using the devices at the same time, I think that would depend on which ID the cruise control is assigned to (so that it would always get priority above the Bluetooth module).
To summarize the questions:
1) Is it possible (and safe) to have both these devices connected to the OBD-II connector at the same time?
2) Is it possible to use them at the same time? Is it common for the diagnostic devices (like the ELM327) to have the lowest ID on the CAN bus to not interfere with other devices on the bus?