The Unofficial VX-1R Modifications Page     This Page best view with 800x600     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     [HOME]    [DISCLAIMER]    [EMAIL ME]   This Page Last Updated:   11/26/98