User Guide

Data Communication and Host Modes
Rev 3.0B Feb.08 67
• SettingtheStartupModeDefault(M D)to3(UDP)sothat
aUDPsessionisenteredautomaticallywhenthemodem
registersontothenetwork.Serialdatawillbesenttothe
IP/portspecifiedinS53.
IncomingUDPpacketswillbeprocessedouttheserialportif
• UDPautoanswerisenabled(S82=2);
• ThedestinationIPaddressmatchesthatinS53(ifFriends
Modeisenabled,theIPaddressalsoneedstobepresent
ontheFriendsList);
• OrallowanyIPisset(AIP=1);
• ThemodemisinATmode(notinacurrentUDPorTCP
session).
UDPpacketassemblyisaffectedbythevaluesofS50(PAD
ForwardingTime‐out)andS51(PADForwardingCharacter).
Datareceivedintheserialbufferwillbetransmittedwhenthe
idleinter‐charactertime‐outspecifiedinS50(intenthsof
seconds)occursorwhenacharacterisreceivedthatmatches

S51(ifnon‐zero).
UDP Auto Answer
UDPautoanswer(previouslycalledUDPhalf‐open)isset
withS82=2.Whenset,thePinPointXwillautomatically
establishaUDPsessiontothesourceIPaddressandportof
theUDPpacketreceived.ThePinPointXwillremain“locked”
tothisoneremoteIP/portuntilnodataissent
orreceivedfor
thetimeintervaldefinedintheUDPautoanswertime‐out
(S83).Duringthissession,packetsfromotherIP/port
addresseswillberejected,unless*UALLisset.Whetherornot
anincomingpacketwillcausethemodemtoenteraUDP
sessionisalwaysdependentonthe
S53andAIPsettings.
TheNormalUDPMode(MD3)canbecombinedwithUDP
autoanswertocausetheincomingserialdatatobesentin
UDPpackets(insteadofbeingtreat edasATcommands),while
allowingsessionstobeestablishedfromdifferentUDP
sources.AUDPsessionwillbeinitiatedeitherbyincoming
serial
dataorbyanincomingUDPpacket.Thesession,started
byeithermethod,willbeterminatedwhennodatahasbeen
sentorreceivedfortheS82period.Oncethesessiontermi
‐
nates,anothermaybeinitiatedbyeithermeans.
Whenidle,afterthetime‐outhasoccurred,themodemisinAT
commandmodeontheserialport,andanyvalidATcommand
maybeenteredduringthistime.