[NA-User] MFJ-434 Voice Keyer

David A. Pruett k8cc at comcast.net
Mon Dec 8 16:13:36 EST 2003

At 11:41 AM 12/8/03 -0500, you wrote:
>Picked up an MFJ-434 Voice keyer (5 message model) at a local Hamfest over 
>the weekend.  Does anyone have the pinout info for the LPT connector?  (It 
>may be in the NA manual, but I misplaced it or loaned it out, since I 
>can't find mine.  I did find a schematic online for the 4 message 
>model.)  Also, anyone have a source for the required 8 Pin IDC 
>Connector?  Probably not an item Radio Shack would carry.


The NA manual describes the connector info for the LPT connector on the 
computer.  With my MFJ-432 (the 434's predecessor) it was easy to figure 
out how to build an interface with the info in the manual.  (The 432's 
manual has a full schematic PLUS the pinout info for the remote connector.)

The remote connector on the 432 was a common .100 spaced single row header, 
which is available from a number of suppliers (I think the 432's is six 
pins).  I found mine from AMP at the local electronics part store (not 
Radio Shack).  I'm sure Digi-Key has something appropriate.  Looking at 
their catalog I would suggest (in an 8-pin) something like Digi-Key P/N 
A3017-ND, which is AMP P/N 1-87499-3.  It's only $.61, plus you need the 
crimp terminals.

IMHO, getting the MFJ-434 working with NA is well worth the effort.  An 
outboard voicekeyer driven from the LPT port is awfully flexible - no ISA 
slot issues, will work with a laptop, and most contest logging software 
supports the protocol which NA invented.  I have gotten an awful lot of 
good out of my MFJ-432 from WP3, VE1, K8CC and numerous MRRC Field Days.



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