RS-232 D-9 Connection for data transfer

Thread Starter


Joined Jun 24, 2014
Dear all,

I am trying to make data transfer cable for sound level meter (LArson Davis 870B). The pin put they have given in manual are attached. I need to know which pins to connect. I am sure that 8 and 9 are not relevant.

Thanks help will be much appreciated.



Joined Jul 18, 2013
That is non standard RS232 DB9 pin out, generally using 3 wire transmission, the handshake is jumpered, but the pins do not relate to the standard.
For null modem where 2,3 & 5 (gnd) is used and 1-4-6 and 7-8 would be jumpered?
For DB25 it would be transmission 2,3 & 7 and 4-5 and 6-8-20 jumpered.
But the pin designations in this case cannot apply. Unless 4-5-6 H.S. are jumpered?