A two-way communications means permanently installed in the car shall be provided to summon dial or call (one or the other, or both) personnel who can take the appropriate action 24 hours each day. The two-way communications means shall not be transmitted to an automated answering device. A telephone may be connected to either a cellular network, VOIP, or a central telephone exchange shall be installed in the car.

If the normal power source for the communications means fails, the communications means shall automatically transfer to a source of power capable of providing service for at least four hours.