Spectra Engineering MX800 - 7.1.4 CN4 DB9 Male RS232 Connector; RS232 Serial Port Functionality; CN4 Connector Jumpers

Technical Manual Appendices
© SPECTRA ENGINEERING 2006 Revision 4.2.3
101
Note When the front panel channel select option is fitted, input port should
not be used from the external connector CN3 as it is wired to the
thumbwheel switch.