[TenTec] Iambic Keying Mode A versus Mode B

[DJ5IL at aol.com]

Hi,

an elbug with two levers is called squeeze- or "iambic" keyer. Squeezing
the levers initiates a dot-dash or dash-dot sequence dependent on the lever
that's been pressed first. "Iambic" is derived from the iambus, a meter with
alternating short and long syllables. Hence, for morse code characters with
alternating elements iambic keying is very effective and needs much less
movement of the hand than a single-lever keyer.

There are two modes how elbugs interprete iambic keying. These modes
differ in the way the elbug reacts after release of the paddles. Genererally,
an elbug can build two different "elements": dot and dash. In "mode A" the
keyer simply completes the element that has been in progress when the
paddle was released. In "mode B" however, the keyer generates one
additional element, in fact the complementary to the element that has been
in progress when the paddle was released. So, if you squeeze both levers
and release them while a dash is generated, the dash is completed and in
addition a dot is generated. Consequently, in "mode B" you have to (!)
release the levers for example during the second dash of a "C", the dash
of an "R" or the dot of a "K". The original Curtis-Chip operates in mode A,
the WB4VVF Accu-Keyer in mode B.  The CMOS Super-Keyer allows
to select either mode with various dot/dash-memory combinations.

73
Karl, DJ5IL