DICA 7000 ISDN Extender
The DICA 7000 is designed to extend the range of ISDN basic-rate
interface S/T facilities over non- ISDN links, such as leased
lines, radio or satellite. The converters always work in pairs,
extending a single BRI line over an isochronous (duplex,
synchronous, transparent) transmission link.
Different software configurations are available offering different
functionality. For example :
Transparent Extension Optimised
Extends 1B+D* (one x 64K data + signalling) over 64 Kbps, or 2B+D*
(two x 64K data + signalling) over 128Kbps. This is the most
bandwidth efficient way of extending ISDN, as it requires exactly
64 or 128Kbps to extend ISDN. However, there are two restrictions.
Firstly, the hub site must generate the clock. Secondly, this
solution is not ideal for cryptos such as BRENT, due to the way the
DICA unit embeds the signalling in "quiet" patches in B channel
traffic.
Transparent Extension Standard
Utilises 96Kbps or 160Kbps to extend a full Basic Rate Interface
including full signalling and working with a wide range of clocking
scenarios. This configuration is perfect for all ISDN Extension
applications.
Network Function
is just one example of alternative configurations. The DICA 7000
can be interfaced to bandwidth on demand networks such as DAMA
satellite, or to networks where both sides have no access to ISDN,
but both need to use ISDN interfacing devices to communicate with
each other eg. VTC or crypto voice.
