Cessna TURBO CENTURION T210M 1978 Pilot Operating Handbook page 317

PILOT'S OPERATING HANDBOOK CESSNA 800 ALTITUDE
SUPPLEMENT ENCODING/ ALERTING/PRESELECT
SUPPLEMENT
CESSNA 800 ALTITUDE ENCODING
(Type EA-801 A)
WITH
ALTITUDE ALERTING/PRESELECT
(Type AA-801 A)
SECTION 1
GENERAL
The Cessna 800 encoding altimeter (Type EA-801A) is an electrically
driven instrument that senses airplane altitude and provides the pilot with
a visual display of the altitude. It also includes an optical encoder which
automatically produces a logic code corresponding to the sensed altitude.
This code is supplied to the Air Traffic Control Radar Beacon System
transponder in the airplane to generate replies to Mode C (altitude
reporting) interrogations from the ground radar. A second altitude infor-
mation output from the altimeter can be coupled to airplane accessory
equipment such as an altitude alerter or an autopilot altitude preselector
circuit.
The altitude alerter (Type AA-801A) is an accessory unit used with the
Cessna 800 encoding altimeter to supply a preselected altitude capture
signal to arm the altitude hold function of the Integrated Flight Control
System. It also provides visual and aural warnings as the airplane
approaches and then deviates from the selected altitude.
The encoding altimeter is a panel-mounted barometric altimeter with
an altitude range of -1000 to +35,000 feet. Altitude is displayed by a dial and
a digital readout. The dial is graduated in 10 numerical divisions which
represent increments of 100 feet, with subdivision markings for every 20
feet; the dial pointer completes one revolution for every 1000 feet of altitude
change. The digital readout displays airplane altitude in increments of
hundreds and thousands of feet only. Friction-induced lag and jumping of
the display is reduced by the use of a combined aneroid sensor and motor-
driven display. Electronic damping circuits in the unit insure that the
display follows altitude changes rapidly with no overshoot. When power is
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