# 7. CAN bus

| | |
|---|---|
| CAN 1 | Transceiver fitted; terminals CAN H and CAN L; the gripper bus in PAROL6 |
| CAN 2 | Controller on the microcontroller, transceiver not populated |
| Bit rate | 1 Mbit/s, set by the firmware |
| Termination | One jumper per bus, **CAN1 JUMPER** and **CAN2 JUMPER**: with the jumper on, a 120 Ω resistor is connected between CAN H and CAN L; with it off, the bus is not terminated on the board |

In PAROL6, CAN 1 runs with 24 V and GND to the M8 socket at the forearm. The firmware addresses one gripper at the
CAN ID the PC's packet names (0 as the grippers ship), sends it a move, a calibrate, a clear-error or an empty
status frame every cycle, and relays its answer to the PC: [CAN bus](https://docs.source-robotics.com/PAROL-docs/1.1/06-peripherals/can-bus/) in the Robot
Manual, and the gripper manuals for the messages themselves.

A CAN bus is terminated at both of its ends, 120 Ω at each. In PAROL6 the ends are the board, with its
CAN1 jumper, and the gripper, with its own termination switch. Nodes in the middle of a longer bus stay
unterminated. The jumpers are on the board figure in [Connectors and pinout](https://docs.source-robotics.com/PAROL-docs/1.1/board/04-connectors/).