Chapter 8 Installing a media bay module (MBM) 135BCM200/400 4.0 Installation and Maintenance GuideBCM400 expansion gateway MBMsMBMs are installed in the BCM400 expansion gateway in the same manner as in the BCM400main unit. Refer to Figure 73 on page 135 and Figure 74 on page 136 for sample MBM layoutsusing the expansion gateway.The following rules apply when using a BCM400 expansion gateway:• All stations must be on the host unit.• Primary rate interface (PRI) PSTN trunking interfaces must be on the expansion gateway.If analog modems are deployed as part of the overall customer configuration and intended to sharePSTN network access with the normal voice trunks, then an exception to the above rules isrequired. In this case, analog stations (for example, ASM8+, GASM8, or even ATAs connected toa DSM16/32) must be configured in the expansion gateway to support the modem connectionsonly. Fax machines or other analog telephones must be connected to MBMs on the host system.Figure 73 BCM400 expansion gateway configurationWarning: Do not attempt to turn on ports requiring a DS30 bus that is already in serviceto another media bay module located on the same BCM system. Doing this results inunpredictable behavior with both modules.DSM32DSM32DSM32DSM32DTMDTMASM8CTM8CTM8ASM8ASM8ASM8Example 1System needs:16 analog trunks32 analog phones128 digital phones10 IP PhonesBCM400 main unitand expansion unitBCM400 expansion gatewayDSM32DSM32DSM32DSM32DTMDTMASM8ASM8DSM32ASM8ASM8Example 2System needs:32 analog phones160 digital phones10 IP PhonesBCM400 main unitand expansion unitBCM400 expansion gateway
