User Manual
GMC-I Gossen-Metrawatt GmbH 61
Technical Data
Data Interface
Type Optical via infrared light through the 
housing
Data transmission 
(data transfer) Serial, bidirectional (not IrDa compatible)
Protocol Device specific
Baud Rate 38,400 baud
Functions –  Select/query measuring functions and
parameters
–
Query/transmit momentary measurement 
data
– Read out stored measurement data
The USB X-TRA plug-in interface adapter (see accessories) is 
used for adaptation to the PC’s USB port.
Internal Measured Value Storage (METRAHIT EXTRA only)
Memory capacity 16 MBit / 2 MBit for approx. 60,000 
measured values with time stamp
Power Supply
Battery 2 ea. 1.5 V mignon cell (2 ea. size AA),
alkaline manganese per IEC LR6
(2 ea. 1.2 V NiMH rechargeable battery 
also possible)
Service life With alkaline manganese: approx. 200 
hours
Battery test Battery capacity display with battery 
symbol in 4 segments:  . 
Querying of momentary battery voltage via 
menu function.
Power OFF function The multimeter is switched off 
automatically: 
– If battery voltage drops to below approx. 
1.8 V
– If none of the keys or the rotary switch 
are activated for an adjustable duration 
(10 to 59 min.), and the multimeter is not 
in the continuous operating mode
Power pack 
connector socket
(METRAHIT E
XTRA 
only) If the NA X-TRA power pack (see 
accessories) has been plugged into the 
instrument, the batteries are disconnected 
automatically.
Rechargeable batteries can only be 
recharged externally.










