ML-20N is a family of n × 64 kbps main link modules that connect Megaplex-2100 and Megaplex-2104 units to high-speed digital data service networks running at sub-E1 rates (128 to 2048 kbps). In addition, ML-20N can provide backup line support for E1 main links over high-speed digital data lines.
The ML-20N modules are available with one or two links, with a choice of V.35, RS-530/RS-422 or X.21 data interfaces. RS-449 interface is also supported via a supplied adaptor cable (see Ordering). These interfaces operate at main link data rates of n × 64 kbps in the range of 128 to 2048 kbps (n=2 through 32). These rates correspond to payload rates of 64 to 1984 kbps (equivalent to that of a full E1). In addition to operation at a user-selected rate, the operation rate can also be selected automatically (any supported multiple of 64 kbps).
The modules provide redundancy between ports on the same ML-20N/2 module or between ports on different ML-20N modules.
Moreover, ML-20N ports can backup E1 ports, such as the ports of the ML-1E1/ML-2E1/ML-8E1 modules.
The ML-20N modules provide link backup for applications where the traffic is normally carried by E1 links (via modules such as ML-2E1). If the E1 link fails, the traffic is automatically rerouted to a leased line or an ISDN dial-up modem connected via the ML-20N port.
