VIMS Communicator Buffered Telemetry Splitter Caterpillar

Buffered Telemetry Splitter
1.1. Theory of Operation
2.1. Routing
3.1. Buffering

Theory of Operation

The VIMS On-Board telemetry port was designed to work with only one device connected at a time. The protocol was also designed in such way that each packet of information that is broadcast by the telemetry port requires a response from the listening device before the next information packet will be broadcast. The buffered telemetry splitter accomplishes two major tasks:

  • The routing of messages between two different inquiring telemetry devices

  • The buffering of messages on any given port.

Note: The buffering of messages on any given port allows free real time communications to occur on the other ports

Each of these major functions is described in the following information:


The VIMS Communicator takes all incoming solicited messages from external devices to the VIMS telemetry port. Then, the VIMS Communicator routes the response from VIMS back to the connected device. In Addition, VIMS messages that are broadcast, are passed to all telemetry outputs.


The reason for buffering telemetry communications is that if an external device stops answering VIMS, then VIMS will stop talking. This is useful for radios that have lost signal. However, when more than one device is on the telemetry port (such as a scoreboard) this causes problems because real time updates are no longer occurring. The VIMS Communicator solves this problem by always answering VIMS telemetry broadcasts. This keeps all external real time dependent devices secure. If a device (such as an wireless radio without a signal) stops responding to the VIMS Communicator, the VIMS Communicator simply starts buffering all the data that is coming from VIMS On-Board so that when the external device begins to respond again, the external device will be quickly brought back to real time status without having missed any data. This device has two buffered telemetry ports with a 100 kilobyte buffer on each port. The display port is not buffered but is kept alive regardless of the state of the two-buffered ports.