4.1 TroubleshootingInstallation Manual 1514.1.3 OperationPROBLEM PROBABLE CAUSE SOLUTION• When using thespeakerphone on an APT,nothing is audible.• The HANDSET/HEADSETselector is set to the"HEADSET" position.• When the headset is not used, set theHANDSET/HEADSET selector to the"HANDSET" position.• When using thespeakerphone/monitormode with a DPT, nothing isaudible.• The "HEADSET" mode isselected by PersonalProgramming, "Handset/Headset Selection".• When the headset is not used, selectthe "HANDSET" mode by PersonalProgramming.• The PT does not ring. • The ringer volume is off. • Turn on the ringer volume.• Originating an outside call,call transfer, or conferencecannot be performed.• The corresponding CObutton does not exist on thePT.• Programme the CO button. Refer to"1.18.2 Flexible Buttons" in the FeatureGuide.• Cannot register the PS. • Wrong PersonalIdentification Number (PIN)is registered to the PS.• Enter the PIN set to the Hybrid IP-PBXinto the PS.• CS is not connectedproperly.• Make sure that the cable is connectedproperly with correct pin assignments.Also, make sure that the cable does notmake short circuits.• Switch all DIP switches off.• PS becomes out of range.• Cannot make calls using thePS.• CS is not working. • Make sure that the cable is connectedproperly with correct pin assignments.Also, make sure that the cable does notmake short circuits.• Switch all DIP switches off.• Location of CS is not good. • Locate the CS properly (refer to "2.7.5Site Survey Using the KX-TCA255/KX-TD7590").• Access system of the PS isnot properly set.• Change the access system setting ofthe PS to the appropriate system orautomatic.• Noise is frequent while usingthe PS.• Conversations disconnectwhile using the PS.• Call handover is notworking.• PS is out of CS coveragearea.• Locate the CS properly (refer to "2.7.5Site Survey Using the KX-TCA255/KX-TD7590").• PS stays out of servicewhen the CS status ischanged from Out ofService to In Service.• It may take about 10 s forCS to start up after thestatus has been changed toIn Service.• Wait until the CS starts up.