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HAM™

 

micro

HAM America, LLC                               Box 1257                                        Geneva, FL  32732

 

 

micro KEYER - Audio Routing settings

 

 
General notes 

micro Keyer provides extensive flexibility in routing audio among the computer sound card, 

transceiver, and station microphone.  This allows customizing the audio configuration to meet 

the needs of a specific software program and operator requirements for particular operating 

mode.

 

 

 

From transceiver through micro KEYER to the computer.

 

micro Keyer always routes audio from the transceiver to the computer sound card; operation is 

"What you hear is what you get."  Receive audio (including monitor audio and sidetone if the 

transceiver supports it) goes to the computer SOUND CARD  LINE IN.  This allows real time 

decoding of digital modes (RTTY, PSK31, etc.) and/or recording the received audio directly to a 

computer file. 

 

An audio cable must be connected from the micro KEYER 

SOUND CARD IN

 jack to the 

computer 

SOUND CARD LINE IN

.   If the computer does not have a LINE input, the 

MICROPHONE input can be used but the micro KEYER end of the cable must remain plugged in 

to the 

IN

 jack. 

 

 

From computer through micro KEYER to the transceiver. 

Audio generated by the computer can be used for several purposes.  For example, it can be 

used as memory voice keyer in voce modes (SSB, AM, FM), or for modulation of digital modes 

(AFSK/RTTY, PSK31, MFSK, etc.).  The micro KEYER provides three audio routing settings: 

Setting A

 disconnects the computer audio and connects the microphone to the transceiver 

microphone input; 

Setting B

 routes the computer audio to the transceiver rear panel audio 

input (PKT or AUX depending on manufacturer); 

Setting C

 routes the computer audio to the 

transceiver microphone  input.  Since the PKT or AUX input of most radios bypasses the 

microphone preamp and other audio processing stages which can distort digital modulation 

generated by the sound card, 

Setting B

 is recommended for digital mode operation. 

 

 

An audio cable must  be connected from the micro KEYER 

SOUND CARD OUT

 jack to the 

computer 

SOUND CARD LINE OUT

 or 

HEADPHONES

 jack. 

 

 

From station microphone to the computer or to the transceiver. 

A microphone which matches the pinout of your radio should be attached to the micro KEYER 

RJ45 connector.  If the transceiver and microphone are terminated with circular 8 pin FOSTER 

connector, the (optional) cable set contains an adapter.  Heil microphones can be used directly 

by plugging them into the EXT MIC jack located on the rear panel of micro KEYER.  

Setting A

 

connects the station microphone to the transceiver microphone jack.  

Setting B or C

 connects 

the station microphone to the computer SOUND CARD MIC IN.  

 

 

When the station microphone is connected to the SOUND CARD MIC IN,  an optional pre-

amplifier can be enabled by moving two internal jumpers to the second position.  The sound 

card microphone input is usually not sensitive enough for low level dynamic microphones (like 

the Heil elements) and the preamplifier needed to provide sufficient drive for sound card 

operation.

 

 

 

An audio cable must be connected from the micro KEYER 

SOUND CARD MIC

 jack to the 

computer 

SOUND CARD MIC IN

 jack.

 

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