THROTTLE COMMUNICATION MODULE (TCM) - Introduction
The Throttle Communication Module (TCM) is an ABS plastic constructed box, that is mounted directly to the forward edge of the throttle quadrant. The TCM contains all the components required to facilitate communicate between the Throttle Interface Module (TIM) and the throttle quadrant. It also enables functionality and power for the operation of the speedbrake.
Although rudimentary in function, the TCM includes a system of three LED lights that can be used for basic troubleshooting (throttle connection and speedbrake operation).
The TCM accommodates three 12-Volt busbars and four relays.
LEFT: Forward section of the Throttle Communication Module (TCM) showing 3 LEDS and five straight-through cables that connect to the Throttle Interface Module (TIM). The TCM is small enough to mount directly to the throttle unit (click to enlarge).
The wires from the busbars are connected to five D-Sub connectors which are mounted to the front of the module.
The five D-Sub connectors are individually labelled and colour coded to connect with the five straight-through cables that are connected to the Throttle Interface Module (TIM).
One 12-Volt busbar (inside the TCM) connects directly with the speedbrake motor located above the TCM on the firewall of the throttle quadrant. This enables power for the movement of the speedbrake lever.
The four relays (on or off) control the logic behind the functionality of the speedbrake as follows:
(i) Speedbrake stowed;
(ii) Speedbrake armed;
(iii) Speedbrake armed annunciator (located on MIP); and,
(iv) Speedbrake deployed/engaged.
LEFT: The inside of the TCM is essentially wiring, busbars and relays. Installing most of the busbars in the TCM frees up considerable space in the Throttle Interface Module (click to enlarge).
TCM - Interface Alert System
The TCM has a very basic Interface Alert System. This system comprises three coloured LED lights. The LED lights are located on the forward portion of the TCM between the straight-through cable D-sub connectors.
For a more detailed review of this system, and to avoid duplication, please navigate to the Interface Alert System (IAS).
Additional photographs can be found in the picture gallery.