RAD Industrial Partner

RAD DXC-30 Modular Digital Cross Connect Digital DIM - Inverse Multiplexer Module Simple Type: Expansion Module

DIM is a digital inverse multiplexer modulefor the modular DXC units. The DIM module, working in conjunction with up toeight E1/T1 ports of DE1B, DT1B, D4E1, D8E1, D4T1, D8T1, D4SL, D8SL, DE3, DT3 or DFSTM-1 modules, enables DXC to function as an inverse multiplexer. DIM transmits a single high-speed data stream of up to 15.36 Mbps over multiple E1/T1 lines. The inverse multiplexing technique breaks down the high-speed signals into multiple E1/T1 lines, and routes these signals over different paths or facilities while ensuring transmission integrity. DIM bridges the bandwidth gap between E1/T1 and E3/T3 traffic, allowing bridges and routers to operate at their fastest rates. The module complies with ACCUNET Fractional T45 service (AT&T), providing a choice of four new transmission speeds that are intermediate between T1 and T3 rates. DIM can also transmit Ethernet traffic over D4SL or D8SL modules. The module occupies a single slot in the DXC chassis. It can be installed in the DXC system together with other modules, to provide a combination of cross-connect and inverse multiplexing capabilities. Differential delays of up to 64 msec between the E1/T1 lines are tolerated. DIM compensates for such delays, and the original stream is reconstructed. DIM is available with a number of options for the user data ports, including an 10/100BaseT Ethernet bridge with VLAN support, an E1 port, or a choice of sync data interfaces: V.35, RS-530, X.21, or HSSI (High Speed Serial Interface). For E1 links, the total data rate is in multiples of 1.920 Mbps, up to 15.36 Mbps; for T1 links, the total data rate is in multiples of 1.472 Mbps, up to 11.776 Mbps. The automatic rate fallback feature ensures that the logical channel remains open even if individual E1/T1 links fail, by automatically dropping to the next lower rate. When failed links are recovered, DIM automatically returns to the original rate. The V.35 and RS-530 channel interfaces terminate in 25-pin D-type female connectors. Pin assignment is compatible with RS-530 specifications. Special adapter cables can be ordered to connect the V.35 channel to standalone V.35 equipment. The X.21 channel interface terminates in a 15-pin D-type female connector. The HSSI channel interface terminates in a 50-pin SCSI-2 connector. The E1 port option enables DIM, working in conjunction with a DT1B, D4T1, D8T1, or DT3 module, to function as an E1 to T1 rate converter. Each E1 frame (2.048 Mbps) received by the DIM E1 port, is converted into two T1 frames (2 × 1.544 Mbps), and then transmitted simultaneously over the two T1 links of the DXC T1 interface module. DIM with the E1 port complies with AT&T TR-54019 for E1 access over T1 facilities. When equipped with the 10/100BaseT Ethernet interface, DIM connects virtual LANs over n × 56 kbps, or n × 64 kbps lines. With the 10/100BaseT bridge DIM filters Ethernet/Fast Ethernet frames, forwarding only frames destined to the WAN. The 10/100BaseT module can also block broadcast and multicast messages.

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