The Experimentation of Editing Cloning Data of VX-7

0. What is VX-7?

VX-7 is domestic (Japanese) version of YAESU's VX-7R. I tested VX-7 for this experimentation, but the most of this description is probably apply to VX-7R.

1. Interface

I made the original interface(I/F) for connecting VX-7 and PC(Personal Computer), because the software or the connecting cable in order to edit the memory of the VX-7 are not sold in Japan.
Using RS-232C / TTL Interface chip (MAX232), my I/F works certainly with any portable PC.

fig 1 Original I/F and VX-7
(connecting via the microphone adapter (CT-91))


fig 2 Schematic of I/F


Principal parts list on PCB
Part Type and constant RMKS
IC1 MAX232 RS-232-C - TTL level converter (Maxim Integrated Products)
IC2 74LS04 Hex INVERTER (Texas Instruments)
IC3 7805 +5V 1A Voltage-Regulater IC (Matsushita)
Q1 2SC2120 Small-Signal NPN transistor (Toshiba)
Q2 2SC2120 (the same as above)
LED11 - LED15 (General-purpose LED) LEDs for line monitor. (LED 14 and 15 are spare for future )
R1 10K (1/4W) -
R2 10K (1/4W) -
R3 47K (1/4W) -
R4 47K (1/4W) -
R5 100K (1/4W) -
R6 10K (1/4W) -
R11 - R15 1K (1/4W) -
C1 2.2uF(50V) -
C2 2.2uF(50V) -
C3 2.2uF(50V) -
C4 2.2uF(50V) -
C5 0.01uF -
C6 47uF(25V) -
C7 0.1uF(50V) -
C8 0.1uF(50V) -
C9 2.2uF(50V) -

2. Protocol of cloning data exchange

1) Condition

19,200bps, 8bits, Stop-bit:1bit, Parity:none, XON/XOFF control:none

When continues transmitting at 19,200bps, VX-7 at receiving end lost some data. So, the suitable waiting time after transmitting each one-character is needed.

2) Protocol

Operation of transmitting end Operation of receiving end
1) Push Power key while pushing [MON]
2) Indicating "CLONE" on LCD.
1) Push Power key while pushing [MON]
2) Indicating "CLONE" on LCD.
3) [V/M]
4) Indicating "CLONE WAIT" on LCD.
3) [BAND]
4) Indicating "CLONE TX" on LCD.
5) Transmitting 1st block of data (10byte).
5) Indicating "CLONE RX" on LCD.
6) Transmitting ACK(06H).
6) Transmitting 2nd block of data (8byte).
7) Transmitting ACK(06H).
7) Transmitting 3rd block of data (16193byte).
8) When it finishes to receive the data, the same operation as the time of "power on"(graphic presentation of opening is shown), it returns to normal mode.
End End
  • bold type:the operation by the user.

3. Software

I wrote the software for loading, saving or analyzing the cloning data of VX-7 by N88-BASIC. N88-BASIC is a kind of Microsoft BASIC(Beginner's All-purpose Symbolic Instruction Code) for NEC's PC-9801 series(very famous and popular Japanene PC in 1980's, but it is not IBM PC clone!).

If you want to download this program, See This page.(but in Japanene....)


Copyright by Heian Software Engineering (C)H.S.E. 2002 Allrights reserved.
A summary in English - Created : Nov 11 2002, Last updated : Nov 16 2002