That is an old computer bus.. but this I am talking is only one wire and I think its a serial communication bus.. I have one device and one of its wire marked as Qbus and I can connect the device to a PC via RS232 through a converter provided by the same company.only Qbus wire and GND is connected to that box. but I can access all the info from that device . also i can program a controller in that device through this Qbus line.
its an OIL & GAS Directional sensor I don't have any details from the supplier side.. tats why I am trying to get the info about it.. when I trace the connector ..I got only this info..its communicating using this line.. I only have the connector details that says QBus..GND, Battery etc..
for the Qbus, there is only one line all other lines I know what it is..and for the communication with PC only this line and GND are used.. no other lines are connected..
I think that there are a lot of proprietary serial busses that no-one has ever published the specifications for. If the original company decided that they would only be making the nodes themselves, or would be charging for use of their design, they keep it secret. I know that my car has a couple of multiplexed busses that aren't CANBUS and are a way of saving wiring, without any thought to expansion.
Sounds similar to the open-drain or open-collector type Icom C-IV buss, a 1 wire serial bus used in many Icom radios. See Ekki's (DF4OR's) Icom CI-V pages.
When I communicate over a 1-wire serial CI-V interface from the PC side I throw away one RX char for every TX char I send because the interface acts like a loopback connector. On the PIC side I have used a single pin (bit-banged Tx & Rx) or standard two pin hardware USART module with a diode on the Tx pin (due to open-drain bus).