Specifications

Excalibur Multirate DAP Installation and Operation
2-4
Non-Interruptive Secondary Channel (Basic DDS and
Clear Channel 64 Kbps)
The Basic DDS Non-Interruptive Secondary Channel (DDSNI) and the Clear Channel 64
Kbps Non-Interruptive Secondary Channel (C64NI) modes provide a non-interruptive
secondary channel over basic DDS or Clear Channel 64 lines in exchange for a small
amount of bandwidth. The DDSNI mode can operate in both point-to-point and
multipoint network configurations. The C64NI mode operates only in point-to-point
network configurations. The maximum main channel (DTE) data rates are listed in Table
2-1.
Table 2-1. DDSNI and C64NI DTE Rates
DDS Line Maximum DTE Rate
2.4 Kbps 2.1 Kbps
4.8 Kbps 4.5 Kbps
9.6 Kbps 9.0 Kbps
19.2 Kbps 18.0 Kbps
56.0 Kbps 52.8 Kbps
64.0 Kbps 57.6 Kbps
The remaining bandwidth is used for framing, out of band RTS-DCD simulation, and the
non-interruptive secondary channel. The non-interruptive secondary channel can be used
for a customer application. The Network Management Controller (NMC) can be either a
CMS network management system or the front panel depending on whether the Excalibur
Multirate DAP is configured for external control (CMS) or RCP control. When
configured for RCP control, the front panel assumes the role of controller and performs
many of the network management functions.
The non-interruptive secondary channel function can be initiated from the front panel of
your local unit or from a CMS network management system.
Note: Either the RCP feature or the CMS network management system can use the
secondary channel. Both should not be active simultaneously.
Rate Adaption is available for the DDSNI and C64NI modes. This feature allows you to
set the DTE interface to operate at a lower data rate than the DDS line rate. The available
DTE data rates are listed in the “Port Rate Configuration” section in Chapter 5.