Dialable Wideband Service; Introduction; Hardware Requirements - Nortel DMS-250 Reference Manual

Dialable Wideband Service

Introduction

This chapter describes how Dialable Wideband Service (DWS) works,
including hardware, translation and routing, and datafill relationships.
Before the advent of Dialable Wideband Service, data transfers used only
DS-0 channels (one 64 kbit/s channel of a 24-channel T1 span) to transfer
data. With PRI, you have the option of combining several B-channels into
one larger channel called an H-channel. Thus, DWS increases the data
transfer rate (by using additional DS-0 channels). The most common
H-channel is H0—six B-channels at a rate of 384 kbit/s. DWS also provides
you with the flexibility of selecting from the channels available for data
transfers.

Hardware requirements

The following DMS-250 switch hardware is required to support the
functionality of DWS:
The digital trunk controller (DTC) for ISDN allows the provisioning of
ISDN PRI trunks on the DMS-250 switch system. The DTC ISDN (DTCI)
provides a maximum of 20 T1 spans, each of which contains 24 channels.
Figure 8-1 shows the relationship of DMS-250 switch DTCIs to T1 spans
and DS-0 channels.
enhanced network hardware on all switches used by DWS
ISDN digital trunk controller (DTCI) and digital trunk controller 7
(DTC7), with an enhanced time switch (ETS) card (NTAX78AA or
NTAX78AB)
6X50AB DS-1 controller cards
DTCIs and DTC7s require the ISDN NT6X01AB or NT6X01AD frame;
backplane wiring is required to support the ETS card for NT6X01AA.
Digital Switching Systems DMS-250 ISDN Reference Manual MWC14 (CSP14)
8-1