--- a/FC-handset-spec	Sun Jun 13 04:10:21 2021 +0000
+++ b/FC-handset-spec	Sun Jun 13 04:57:31 2021 +0000
@@ -1348,3 +1348,59 @@
 will be possible: the battery will need to be connected to the orange power
 input connector, and the control signals for the charging circuit will need to
 be connected to the 2x4 header.
+
+3.5. LCD module and backlight
+
+It is the Mother's desire to finalize the selection of LCD module for the actual
+handset before embarking on the detailed design (as in schematics, BOM and
+layout) of FC Venus, and to implement the final LCD and the final backlight
+circuit on the Venus board.
+
+3.6. Keypad buttons
+
+The complex mechanical arrangement of keypad buttons that will be needed for the
+real handset will NOT be done on the Venus board.  Instead there will be a
+simple 5x5 matrix of buttons in rows and columns, with silk screen labels
+indicating the function of each button, matching D-Sample - the same arrangement
+as on our current Luna platform.  There will also be 3 out-of-matrix buttons for
+PWON, RPWON and RESET.
+
+There will be no keypad backlight on the Venus board.  This secondary backlight
+is not needed for firmware development, as it is not managed separately in our
+fw architecture - instead its control will be absorbed into our R2D BLRR control
+mechanism on the final handset where this backlight will be added.
+
+3.7. Audio interfaces
+
+Corresponding to the 3 audio channels of section 1.7, there will be 3 analog
+audio interfaces on FC Venus: two TRRS jacks and one 2-pin header.  These audio
+interfaces will be as follows:
+
+* The main audio channel (the one that will go to the built-in earpiece speaker
+  and mic in the real handset) will be wired to a TRRS jack exactly like on
+  Caramel2.
+
+* The "official" headset channel (the one that will be a jack in the final
+  handset) will be wired to another identical TRRS jack.  This other jack will
+  need plug insertion detection, signaled to a Calypso GPIO input.
+
+* The output of the loudspeaker amplifier (see section 1,7.2) will be wired to
+  a 2-pin header exactly like on FCDEV3B, allowing the same 8 ohm lab bench
+  loudspeaker to be connected.
+
+3.8. Magnetic buzzer
+
+There will be a magnetic buzzer implemented directly on the Venus board itself
+(not an externally attached component), exactly like on TI's D-Sample board.
+This buzzer will be controlled by Calypso BU/PWT output in the canonical manner,
+allowing the expected sounds to actually emanate when firmware operates the
+old-fashioned Calypso buzzer output.  See section 2.4 for the purpose of this
+hardware provision.
+
+3.9. LEDs instead of vibrator
+
+There will be no vibrator on FC Venus - it is a mechanical function which cannot
+be sensibly implemented on a development board meant for use on a lab bench.
+Instead our Venus board will feature both LPG and PWL LEDs (i.e., LEDs
+controlled by the respective Calypso outputs) exactly like D-Sample, and either
+of these LEDs can be used to simulate vibrator on/off state.