Journal Archive (Newest First)


The Throttle Interface Module (TIM) houses the various interface cards used in the operation of the throttle, including the automation; therefore, it is the most important module.  Additionally, the module incorporates amperage and voltage meters and a Hobbs meter.  The later is used to measure the number of hours that power has been applied to the interface cards.  A system of LED lights (part of the Interface Alert System) also provides a visual warning in the event that a particular system is not functioning correctly.  

This document will essentially provide details concerning the Throttle Interface Module (TIM); however, the module has a close relationship with the Interface Alert System (IAS).

Interface Cards and Functionality

The TIM, in addition to housing one 5 Volt and two 12 Volt power supplies accommodates the following interface cards:

(i)       Alpha Quadrant Cards (2) – Throttle lever automation;
(ii)      Leo Bodnar 836 Joystick Controller card –  Movement of parts & buttons;
(iii)      High speed Belkin hub – Only one USB cable to computer;
(iv)     12 Volt power supplies (2) – Power for various throttle systemsand autothrottle;
(v)      5 Volt power supply – Power for Belkin hub;
(vi)      Phidget 0/0/8 Interface Kit card – Controls stab trim speeds (forward, aft, flaps in/out, CMD A/B);
(vii)     Phidget 1066 Advanced Servo Controller card -  Controls stab trim indicator movement on throttle;
(viii)    Speed Controller cards (3) – Controls variable speed (4 speeds) of trim wheels;
(ix)     Relays (5) – Controls on/off for stab trim variable speed and specific autopilot; and,
(x)      Busbars – As required


The TIM is constructed form heavy duty ABS plastic which has been plastic welded to ensure strength and longevity.  The upper lid is hinged to allow easy access to the inside of the module.  Six thumb screws are used to secure the lid to the lower section. 

LEFT:  Throttle Interface Module (TIM).  The  three coloured 'traffic lights' can be seen as can the two series of LEDS, in-between the main cooling fans, that form part of the Interface Alert System (IAS) ( click to enlarge)

The module incorporates three power supplies.  As such, cooling is necessary when the simulator is operated in a high ambient temperature.  

Two high capacity fans are located immediately above the power supply units, and to provide additional cooling (if necessary), four additional brushless fans are located at each quadrant of the module.  To allow flow through ventilation, four 5 cm sized diameter ‘mouse holes have been strategically positioned along the side of the module. 

To stop any foreign body from entering the module, the ‘mouse holes’ have been protected by low-grade wire mesh that is attached to the ABS plastic.

The four accessory side fans, can be turned off by two toggle switches located inside the module.

Whitespace, Platforms and Ferrules

One of the problems associated with the earlier Interface Master Module (IMM), now discarded, was that there was little space to work around the interface cards and wiring.  To counter this drawback, the module is considerably larger in size than its predecessor.  The extra size ensures there is sufficient ‘white space’ to troubleshoot any possible wiring problems.  Further, to remove any confusion to which wire does what, all wires have been colour coded and labelled.

To facilitate easier removal of any interface card, the cards have been mounted directly to 1 cm high ABS plastic platforms; the platforms (called ‘oil rigs’) are mounted directly to the floor of the module.  The use of a platform to secure the card minimises the possibility of damaging the floor of the module when the card is removed.  It also provides additional depth with which to manipulate wires to and from the card.  To facilitate easy removal of any wires from an interface card, all wires have been crimped using ferrules.

Connection and Cables

All the interface modules incorporate VGA and serial port connections.  This reduces the volume of wiring that leaves the module to various OEM parts. 

LEFT:  TIM with lid raised.  The raised platforms can be observed in addition to the colour-coded D-Sub connectors.  The green button (not illuminated) enables the power to the trim wheels to be cut-off, allowing 'quiet flight' (click to enlarge).

Mating with the D-Sub connections are straight-through cables that incorporate tightening screws.  Once a straight-through cable is attached and secured to the module firewall, there is no chance that the cable will work its way loose causing an intermittent connection.  

The use of straight-through cables ensures the wiring to be relatively neat, tidy and manageable. 

All straight-through cables (5) that are used to control the throttle are connected to the Throttle Communication Module (TCM).  The TCM is a small ABS constructed box that is mounted directly to the forward edge of the throttle unit.  The TCM is the interface between the TIM and the throttle unit.

A single USB cable leaves the module to be connected with the computer.  To facilitate one USB cable philosophy, a high quality powered Belkin hub is installed inside the module along with a dedicated 5 Volt power supply.

Sectors, Traffic Lights and Oddities

The TIM has been designed to be able to turn on and off various sectors that require a specific voltage. 

Whether a sector is powered up (activated) will depend on which of the three illuminated LED buttons are pressed.  Due to the lights resemblance to traffic lights, these button have been called 'traffic lights'; they are located on the rear end of the module. 

Depressing the red traffic light will turn on the 5 Volt sector which will power the Belkin hub and the various accessory gauges (discussed later).  The Green traffic light will engage the 12 Volt sector and the blue traffic light engages only the throttle automation.

The 12 Volt sector includes:

(i)    Speedbrake deployment;
(ii)   Stab trim wheel motor and logic;
(iii)  12 Volt busbar (located in Throttle Communication Module);
(iv)  12 Volt busbar (located in Throttle Interface Module);
(v)   Cooling fans; and ,
(vi)  The parking brake actuator

An oddity is a single green push-in LED light.  This light is located on the opposite side of the module directly below the straight-through cables and their connectors.  If this button is released (light extinguished) the power to the trim wheels is disengaged (relay on/off).  This oddity, although unrealistic, allows the trim wheel to be silenced so that family members are not disturbed, when flying at night, by the noisy rotation of the trim wheels.

LEFT: Accessory gauges on TIM:  Hobbs meter, amperage and voltage gauges (click to enlarge).

Accessory Gauges

Located on the upper lid of the TIM are a number of accessory gauges.  These include a Hobbs meter, a digital clock, and four voltage/amperage gauges.   The Hobbs records the amount of time that the module has had power connected to it while the other four gauges monitor 5 and 12 Volt amperage draw.  A digital clock completes the accessory gauge array.

Power Requirements

The TIM requires 5 and 12 volts to operate.  The TIM is not connected to the Power Supply Rack (PSR) as I wanted the system to be completely standalone.

The TIM accommodates two standard 12 volt power supplies.  One supply is dedicated to provide power to the autothrottle motors while the second 12 volt unit provides power for other throttle components, such as the movement of the speedbrake, stab trim wheels and trim tabs, parking brake light, cooling fans, LEDS, ancillary volt and amp gauges, and the brake mechanism.  The 5 volt power supply is a small 'mini' supply which is dedicated to powering the Belkin powered hub from which the various components connect to.

Location of TIM

The module is mounted on a small three-shelf bench that is located forward of the Main Instrument Panel on the First Officer side. The bench is large enough to adequately store several interface modules while allowing accessibility.

Additional photographs can be found in the picture gallery.