3Com DIGITAL MODEM User Manual

Contents

2-2 CHAPTER 2: INSTALLING AND CONFIGURING THE DIGITAL MODEMTable 2-1 Front Panel LED Indicator DefinitionsLED Color DescriptionPower Yellow Power Indicator. Lit when power is on and remains lit as longas power is available from the ac wall transformer plugged intothe electrical outlet.Test Yellow Self-Test/Status. Flashes when the digital modem isexecuting its power-up self-test or a user-initiated reset. If theresults of the self-test or reset are normal, the LED goes off. Ifthe result of the self-test is abnormal and a fault is detected,the LED remains lit but does not flash.D-Channel Yellow D Channel/Status. Provides a quick indication of the ISDNphysical network interface and D channel status. If the physicalISDN interface is not synchronized or is disconnected, this LEDremains lit.If the physical interface establishes synchronization and theISDN D channel signaling procedures are not properlyestablished, the LED flashes.Once the physical and D channel signaling are synchronized,the LED goes off.If any physical loss of framing occurs, the LED lights; if there isa loss of D channel signaling, the LED flashes.B-1 YelloworgreenB-1 Channel Indicator. Indicates the activity state of the B-1channel of the ISDN interface. Green indicates acircuit-switched data call. Yellow indicates a circuit-switchedvoice call. If a call is in a dialing state, the LED flashes. When acall enters the active state, the appropriate LED color stays lit.When the call is disconnected, the LED goes off.B-2 YelloworgreenB-2 Channel Indicator. Indicates the activity state of the B-2channel of the ISDN interface. Green indicates acircuit-switched data call. Yellow indicates a circuit-switchedvoice call. If a call is in a dialing state, the LED flashes. When acall enters the active state, the appropriate LED color stays lit.When the call is disconnected, the LED goes off.