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CBO-232: new RS-232 CARD for JRC NRD-525.


With this card, you can remote your NRD-525 with a RS-232 terminal or a computer.
You can access to the frequency, read/write memory, mode, IF filter, attenuator and AGC...

Excel sheet read/write NRD-525 memories and VFO.

- WARNING : if the serial number of your JRC happens to be any of BR36071 through BR36120, the CPU EPROM must be replaced.
- The old version 7DEJD0072 does not work correctly in 1200 Bauds. (See 2764 EPROM ).

What are the differences between the CMH-532 and the CBO-232 card ?

JRC CMH-532New CBO-232
Problems with 7DEJD0072 CPU EPROM (1200 Bauds)YESYES
Replacement of the CPU EPROM (if BR36071 to BR36120)YESYES
Direct installation on the CMH-632 cardYESYES
300 and 1200 Bauds speedYESYES
2400 and 4800 Bauds speedNOOnly with the V2.0 and after
CPU EPROM Version.
Based on a 8251 circuitYESYES
Slow speed LEDNOYES
RS-232 outputsOptical isolationClassical circuit MAX232
on socket
RS-232 connectorSpecial JRC
7 pins DIN connector
with 9-pole SUB-D female cable
RTTY demodulator output (with the CMH-530 card)YES (pin 10)YES (pin 6)

CBO-232 card specifications
  • Based on a 8251 circuit and a programmable divider.
  • RS-232 outputs with a classical circuit MAX232.
  • Quartz reference: 3,6864 MHz.
  • This card is installed in the CMH-632 connectors.
  • The J47 connector is compatible with the JRC cable referenced H-6ZCJD00141.
  • 7 pins DIN RS-232 connector, with 9-pole female Sub-D RS-232 standard cable (DB9).
  • RS-232 configuration: 8 data bits, 1 stop bit, no parity.
  • 300 and 1200 Bauds.
  • (Optional 2400 and 4800 Bauds). (*) )
  • An onboard LED (SLW) indicates the slow speed.
  • If you have the RTTY CMH-530 card:
    • Characters converted can output to the RS-232,
    • An auxiliary output can be use by an external device to decode others modes (RTTY ASCII, CW...).
  • Notices : & .

  • For information :


(*) After the V2.0 CPU EPROM version, you can access and use the 2400 and 4800 Bauds rate.


This card is installed in the CMH-632 card (J45 and J46 connectors).

Plastic spacer.

2nd photo.

=> =>
CBO-232 - CMH-632 Insert
Cards and plastic spacer.

7 pins DIN connector on the rear panel :

Internal DIN cable (soldering side) :

5 pins DIN connexion with a 9-pole female SUB-D connector femelle 9 broches (soldering side) :
DIN connector to the JRC receiver,
SUB-D connector to a computer.



F4EZC [email protected]