K1EL K45 CW Modem Manual K45
K-45 User’s Manual - Rev A
6/6/2021
Page 28
Appendix B - K45 Modem Quick Start
Interconnection Diagram
The following diagram illustrates a basic K45 set up. The paddle is optional and is not a requirement. A PTT
connection would not be required for normal CW keying of a transmitter or transceiver, the PTT output is
used primarily in RTTY mode, HSCW mode, or to key an amplifier or antenna relay. The keying output of the
K45 is capable of keying virtually any solid state or grid block transmitter and is optically isolated from the
K45 chassis for safety.
Gnd
Iambic
Paddle
USB
Host I/F
(power)
Dah
Host
Keying
Output
Keyboard
Audio
Input
Paddle
Input
Gnd
PTT
Ke y
Audio
Input
N/C
Ke y Line
to XCVR
K45 Back Panel
Dit
AF
USB
Ke yboard
Gnd
Figure 26 - K45 CW Keyboard Hookup Diagram
Which Keyboard to Use
The K45 will accept just about any wired or wireless USB keyboard. Surprisingly, most wireless USB
dongles draw significantly more current that a standard wired keyboard. This may be a consideration for
portable battery operations.
Power Supply
The K45 is powered through the host USB connector. This means it can be powered by connecting it to a
host PC, a USB charger, or battery pack. The current draw of the K45 is low, about 120-150 mA so even a
small USB charger will work fine. Please use a good quality USB charger, one for a dollar might not be a
good choice.
Power On/Off
The K45 will power up as soon as it is plugged into a USB power source and will remain on. It can be put
into a low power sleep mode by pressing the ESC-Y command or by holding the encoder button down for 3
seconds after the configuration menu appears. In sleep mode, the display backlight is turned off and other
electronics set to a low power state. To wake the K45 up, simply turn the encoder one or two clicks. The K45
can be configured to automatically go into sleep after a specified time of inactivity. This option can be found
in Configuration Menu #4:Sleep.
Sidetone Speaker
The sidetone speaker on the K45 provides audio feedback as Morse is transmitted. There are four sidetone
volume levels that can be set via an entry in Configuration Menu #3:STvolume. In most configurations, the
K45’s sidetone should be turned off and the sidetone built into your transceiver will be used instead.
However, K45 sidetone is useful for code practice or testing purposes. Please note that the internal speaker
can’t be used for receiver audio. (This was a common question from K42 and K44 owners)
Transmitter Connection
This is highly transmitter/transceiver dependent. It can be as simple as making up a cable with an 1/8-inch
mono jack on each side or as complicated as using stereo jacks and modifying the keying mode in your
