User Guide

Data Communication and Host Modes
Rev 3.0B Feb.08 73
assubnetmasks,routers,etc.)toeachcomputerordevice
withouttheneedtosetupeachspecificallyorkeeptrackof
whataddresseshavealreadybeenused.
Inadefaultconfiguration,thePinPointXactsasaDHCPhost
toanydeviceconnectedtoitsports,providingthatdevicewith
anIPaddresswhichcanbeusedtocommunicateonthe
Internet.InPublicMode,thatwillbetheIPaddressassigned
bythecellularnetwork.InPrivate
Mode,thatwillbetheIP
addressdefinedin*HOSTPRIVIP.
1. WhenthePinPointXregistersonthecellularnetwork,itis
assignedanIPaddressfromAT&T,let’ssay A.B.C.D.
2. ActingasaDHCPserver,inPublicMode,whenthe
PinPointXreceivesaDHCPrequestfromanEthernet
device,ithandsofftheassignedaddresstothedeviceand
setsupthedefaultgatewayaddressasA.B.C.1.Ifthe
fourthoctetisalreadya1,itassignsA.B.C.2as
therouter
address.
3. ThePinPointXalsosendsa/24netmask(255.255.255.0by
default)andsetsupastaticroutewhichmaps
192.168.13.31(ortheaddressconfiguredwith
*HOSTPEERIPifitischanged)toA.B.C.1(orA.B.C.2if
thatwaswhatthegatewayaddresswasgivenas).
Tip: When PPPoE is used with the PinPoint X, DHCP is not needed.
A tunnel is set up connecting a device (such as your computer or a
router) with the modem. The device will then simply use the MAC
address of the PinPoint X to send all outgoing packets.
Keepalive
Keepaliveisusedtotesttheconnectiontothecellularnetwork
bypinginganIPaddressafteraspecifiedperiodofinactivity.
Keepaliveisonlyrecommendedforuserswhohavearemote
terminatedmodemthatinfrequentlycommunicatestothe
networkorifyouhaveexperiencedissuesovertimewherethe 
modem
cannolongerbereachedremotely.
WhenKeepalivepingstheIPaddress,anacknowledgement
indicatesthereisanactiveconnectiontothenetwork.Ifthe
PinPointXdoesnotreceivearesponsefromtheIPaddress,it
willmakeadditionalattemptsaccordingtoabackoffalgorithm
beforedeterminingtheInternetconnectionisnotfunctioning
properly.Ifit
determinestheconnectionisnotfunctioning,the
modemwillthenattempttoreconnecttoAT&Ttoreestablish
IPconnectivity.