Avionics Bending: Honeywell CD-800 Display Unit

Honeywell CD-800 Display Unit

Every now and then I need to take my mind off the L-1011 for a moment and go play with something totally different. Today I powered up a Honeywell CD-800 Display Unit. They are pretty neat little terminal units most frequently used on Gulfstream business jets and would be connected to something like a Honeywell NZ-920 Navigation Computer. While it is not totally unrealistic that such an avionics package could have been installed on the L-1011 I have not found any evidence that it was ever considered. The FMS on the L-1011 typically consisted of, for example, a Litton INS. However this unit is still a lot of fun and has a lot of ARINC 429, RS424 and RS232 inputs and it might become a good fit for the next project, the MD-83 project.

The CD-800 Control Display Unit (CDU) is the pilot interface with the FMS. The CRT displays relative flight information to the pilot. The pilot enters alphanumeric data into the system via the full alphanumeric keyboard. This data appears in the scratchpad to be line selected to the appropriate position on the CRT display. (from Honeywell Maintenance Guide)

Honeywell CD-800 Annunciators

Annunciators - The six annunciators located at the top of the CDU keyboard panel operate independently from the CRT and keyboard. Lighting of the annunciators is initiated by the navigation computer or performance computer via the RS422 serial data link. The two colors used for annunciations are white and amber. White indicates an advisory type annunciation, and amber indicates an alerting type annunciation (810 and up only). (from Honeywell Maintenance Guide)

Honeywell CD-800 Without Navigation Computer

Here it the block diagram for the unit:

(from Honeywell Maintenance Guide)