Chapter 2 Telephony hardware 49
Installation and Maintenance Guide
Digital drop and insert MUX (DDIM)
The digital drop and insert MUX (DDIM) module enables a Business Communications Manager
system to share its connection to a universal T1 network with a local area network (LAN) to
provide a combination of voice and data channels.
The DDI MUX:
• provides the functionality of a DTM media bay module (T1 digital lines only)
• splits the incoming T1 line so that some of the lines are used for voice traffic and some of the
lines are used for data traffic
• provides either the (Channel Service Unit) CSU or (Data Service Unit) DSU functionality to
support connections to data terminal equipment (DTE), such as a router or a bridge
• connects to network devices that supportV.35 interfaces
• provides end-to-end transparent bit service
• supports loopbacks between the Business Communications Manager and the internal Business
Communications Manager components, and between the Business Communications Manager
and digital terminal equipment
Figure 23 Digital drop and insert (DDIM) faceplate LEDs and connectors
RxDTxD RTS CTS DCD DSR TM10101
Data module serial port
Power LED
Status LED
In Service LED
Loopback Test LED
Continuity Loopback
Receive LEDs
Transmit LEDs
Loopback
RJ48C digital telephone line
connector
