Introducing FC-HDS4 headset

Mychaela Falconia mychaela.falconia at
Sat Nov 6 20:30:35 UTC 2021

Hello FreeCalypso community,

I got an update regarding one of the necessary accessory pieces for
our FC hardware solution: the special wired headset.  I am working
with a Chinese manufacturer of wired headsets to produce a custom one
for FreeCalypso, a headset I named FC-HDS4.  The key distinction
between FC-HDS4 and the historical headsets used with Mot C1xx and
Pirelli DP-L10 is that FC-HDS4 features a 2.5 mm plug of TRRS type,
in the same pinout as used by iWOW on their DSK, and the 32 ohm
earpiece speaker has both of its legs brought out on individual wires,
as opposed to one leg being forced to GND.  FC-HDS4 won't work in the
headset jack of any historical phones (not Mot C1xx, not Pirelli
DP-L10, not any other known model), but it works with our current
Caramel2 development board (plugs into the EAR/MIC jack), eliminating
the dependence on historical iWOW headsets of which there are only two
in the world.  FC-HDS4 will also be a required accessory for our
upcoming FC Venus development board.

Yesterday I received the first two sample pieces of FC-HDS4 from the
Chinese manufacturer, and I started the necessary testing process.  So
far all tests are passing, and I am getting ready to give the go-ahead
to the manufacturer to produce 100 pcs of our headset.  I put together
an initial audio mode config for FC-HDS4 on Caramel/C2 boards (see
fc-audio-config Hg repository), and with this configuration in effect,
the audio quality is good both to the headset user (development board
operator) and to the party on the far end of the call.

Aside from this headset, the other prerequisite for FC Venus is the
custom metal bracket or strap for holding the bottom part of our new
Formike KWH020ST23-F01 LCD module in place.  A while back I engaged
with a local-to-me sheet metal fabrication shop to design and produce
this simple metal piece, but they dropped the ball on the project, so
I need to follow up and hammer on them to get it done.

Hasta la Victoria, Siempre,
Mychaela aka The Mother

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