Chapter 2 Introducing the BCM hardware 63BCM200/400 4.0 Installation and Maintenance Guide• provides the functionality of a DTM (T1 digital lines only)• splits the incoming T1 line so that some of the lines are used for voice traffic and some of thelines are used for data traffic• provides either the channel service unit (CSU) or data service unit (DSU) functionality tosupport connections to data terminal equipment (DTE), such as a router or a bridge• connects to network devices that support V.35 interfaces• provides end-to-end transparent bit service• supports loopbacks between the BCM system and the internal BCM components, and betweenthe BCM system and digital terminal equipmentFigure 36 shows the DDIM faceplate LEDs and connectors.Figure 36 DDIM faceplate LEDs and connectorsBCM400 expansion gatewayThe BCM400 expansion gateway is available in standard and redundant configurations forBCM400 systems only.The BCM400 expansion gateway kit (North America only) consists of a BCM400 main unit andenough VoIP gateway trunk authorization codes to enable 48 ports of VoIP trunks. The BCM400expansion gateway, combined with the BCM400 host system, provides a maximum of 192 TDMsets, instead of 160, while communicating to the PSTN through TDM trunks on the expansiongateway. The VoIP trunks connect the two systems and allow the BCM400 expansion gateway totandem from IP trunks to the PSTN/TDM trunks (see Figure 37 on page 64).The addition of a second BCM400 expansion gateway provides up to two T1 PSTN trunks. Thisreleases enough system resources on the host BCM400 main unit for the addition of 64 digitaltelephones.RxDTxD RTS CTS DCD DSR TM10101Data module serial portPower LEDStatus LEDIn Service LEDLoopback test LEDContinuity loopbackReceive LEDsTransmit LEDsLoopbackRJ-48C digital telephone lineconnector
