35BCM50 Installation and Maintenance GuideChapter 2Introducing the BCM50 hardwareThe BCM50 is a modular telephone system that can expand as your telephony requirements grow.Refer to the following sections for information on the BCM50 hardware components:• “Main units”• “Expansion unit and media bay modules” on page 38• “BCM50 hardware” on page 46• “BCM50 components” on page 49• “Field-replaceable units” on page 53• “Telephones and adapters” on page 54Main unitsThe main hardware component in the BCM50 system is the main unit. There are three types ofmain units:• BCM50 main unit (with Telephony only)The BCM50 main unit provides call processing and simple data networking functions. Itprovides connections for 12 digital telephones, 4 (PSTN) lines, 4 analog station ports, and 4connections for auxiliary equipment (auxiliary ringer, page relay, page output, and musicsource). The BCM50 main unit does not have a router, but it does have 4 LAN ports: one is theOAM port for technicians, and the other three are for basic LAN connectivity. See Figure 1 onpage 36.• BCM50a main unit (with ADSL router)The BCM50a main unit provides all of the same core functionality as the BCM50 main unit,and it also has an integrated ADSL router for advanced data applications. For detailedconfiguration information, refer to the BCM50e Integrated Router Configuration Guide(N0027182). See Figure 2 on page 36.• BCM50e main unit (with Ethernet router)The BCM50e main unit provides all of the same core functionality as the BCM50 main unit,and it also has an integrated Ethernet router for advanced data applications. For detailedconfiguration information, refer to the BCM50e Integrated Router Configuration Guide(N0027182). See Figure 3 on page 36.Refer to Table 1 on page 37 for descriptions of the three main unit ports and connectors.A main unit contains the following field-replaceable units:• 1 programmed hard disk• 1 cooling fan• 1 router card (BCM50a and BCM50e only)
