MasterclockGMRUserManualv2–2016.
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StandardI/Oconnectionsusingoptional
DB9BreakoutAdapter(GMR1000only)
1‐TC‐OUT(NEG)*
2‐RS232RX(DTE)TX(DCE)**
3‐RS232TX(DTE)RX(DCE)**
4‐RELAYCOMMON*
5‐GND
6‐TC‐OUT(POS)*
7‐TC‐IN(POS)*
8‐TC‐IN(NEG)*
9‐RELAYIN/OUT*
*ifinstalled
**basedoninternaljumpersetting
NMEAandtheRS‐232Interface
NMEA
InordertoreceiveNMEA(NationalMarineElectronics
Association)0183sentences(messages),theRS‐232
interface(DB‐9maleconnector)maybeusedtoconnect
yourPCwithyourGMR.UnlesstheGPSoptionisincluded,
onlyZDAsentenceswillbeoutputtedastheycontainonly
UTCtimeanddatesignals.ThesearecreatedbytheGMR.
Othersentenceswithlatitudeandlongitudedataareonly
availablewiththeGPSoption
Note: The device system cannot receive 2 NMEA message
per second when locked to 1 PPS pulse input.
SERIALPINOUTFOR
RS‐232
TheGMRserialportpinoutsaredefinedatleft.Fora
GMR1000,RS‐232communicationsfromastandardIBMPC
orcompatiblehostcomputercanuseastraight‐thrucable(3
wiresonly:pins2,3and5).ForaGMR5000anullmodem
cablemustbeused.
ThedefaultcommunicationsettingsfortheRS‐232portare:
9600baud,8databits,1stopbit,noparity.
The RS‐232 port can be configured for baud rates of 4800,
9600, 19200, 38400, 57600 and 115200, along with 7 or 8
data bits, 1or 2stop bit. Theparity bitscan beselected as
None,Odd,andEven.
F
OROTHERTYPESOF
RS‐232RECEIVERS
itmayormaynotbenecessarytousinganullmodemcable.
Remember,onaGMR1000,onlyathreewirenullmodem
cablemaybeused.
• Ensurethehostsystemcancommunicateviastandard
RS‐232at4800baud,8databits,Istopbit,noparity.
• Pins2an
d3mustuseRS‐232voltagelevels.TheGMR
cannotdecodeTTL‐levelserialcommunicationsatpin2
and3oftheDB‐9connector.
• Ensurethatanycableyouareusingforcommunication
withtheGMRiswithintheRS‐232standardlengthandisa
workingcable.
• Theinterfacemayrequireanullmodemca
ble.
• A“nullmodem”3‐wireserialcableorsimpleRS‐232cable
utilizingpins2,3and5onlyshouldbeused
DB‐9
Pin
Signal
GMR1000signalname
(DCE)
2 TxD TransmitData
3 RxD ReceiveData
5 SG Signal/SystemGround
DB‐9
Pin
Signal
GMR5000signalname
(DTE)
2 RxD ReceiveData
3 TxD TransmitData
5 SG Signal/SystemGround