Guralp Systems CMG-3T - Manual (Page 49)

Operator's guide
26 RS232 ground (RS232 control interface option)
In sensors with the RS232 control interface option, the RS232 ground
line (pin 26) is isolated from the other ground lines (pins 4 and 8)
using 10 nF decoupling capacitors.
6.3 Sensor output (waterproof connector option)
Waterproofed models have a 32-pin waterproof connector in place of
the 26-pin output connector. These instruments are supplied with an
adapter cable for connecting to a standard digitizer input.
The pin connections are:
Pin Function
1
Mass position, N/S channel
2 Lock
3 BUSY LED
4 Logic ground
5 Mass position, E/W channel
6 Power –ve (not used in sensors with internal DC-DC converters)
7 RS232 transmit from instrument (RS232 control interface option)
8 Signal ground
July 2009 49