The Unofficial VX-1R Modifications Page
 
 
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Schematic diagram for PC programming cable.
 
 
 
 
PC Programming Parts List
 
Q1   2N2222
Q2   2N2222
Q3   2N2222
Q4   2N2222
Q5  Not Used
Q6   2N3906
Q7   2N3906
D1    1N914
D2  1N751A
D3   1N914
D4   1N914
 
R1   47K
R2   47K
R3   10K
R4  100K-120K
R5   470K
R6   47K
R7   47K
R8   47K
R9  100K
R10  100K
 
 
.  The abbreviation NC means no connection.  The DB9 connector can be
Radio Shack part # 276-1538 or equivalent.    A good place to start looking
for the 4 conductor plug is Tower Electronics: 1-800-662-3422.  The 2N2222 can
be substituted for any general purpose NPN transistor, while the 2N3906 can
also be substituted for any general purpose PNP transistor.  D1,3,4 are general purpose silicon
diodes.  D2 is any 5.1V zener diode.  All resistors are 1/4 or 1/8watt - 5% tolerence resistors.  This
PC programming cable can also be built with SMT (Surface Mount Technology) parts if desired.
 
 
 
 
 
The interface is a bidirectional level converter, changing TTL-level to RS232, and vice versa.  The supply
voltage comes from RTS, CTS and DTR and is stabilized with D2 to 5V.  Q1 works as a simple switch,
getting the data viz R8 from the PC.  In the opposite way Q2 drives the push pull stage Q6 and Q4.
This cable should work whth the Yaesu FT-50, FT-10, and similar radios
 
 
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This Page Last Updated:   11/26/98