Switched 56 - Telos Zephyr User Manual

SWITCHED 56

Switched 56 is a transition technology which is being offered primarily in areas where
ISDN is not available. As the name suggests, this is a service which permits a single bi-
directional digital data stream to be sent at a 56kbps rate. It can use either one or two
copper pairs ("2 wire" and "4 wire", respectively), depending upon the particular
Central Office configuration. In most areas, switched 56 and ISDN are "inter- worked"
within the Central Office switches, so that subscribers of both services can connect to
each other (at a 56kbps rate, of course).
A switched 56 line requires a Channel Service Unit / Data Service Unit (CSU/DSU) to
interface the digital line with the Zephyr.
These come in two varieties: two- wire and four- wire. The one you need depends upon
the service style offered by your telephone company.
In many cases you can purchase this equipment from your Telos Systems dealer. Some
manufacturers for these Switched- 56 CSU/DSUs are:
Adtran
901 Explorer Ave
Huntsville, AL 35806
800- 827- 0807
Adtran makes all sort of equipment for the telecom industry. The telcos buy equipment
from Adtran. Reputable company.
INC
Integrated Network Corp.
757 Route 202/206
Bridgewater, NJ 08807
+1 908.218.1600
This company offers high- quality and, in our experience, excellent customer support.
98
Section 6
V.35/X.21
PORT1
INTERFACE
(MINI-DB40)
TELOS
PORT2
ZEPHYR•
(NOT USED
FOR ENCODE)
Typical setup for mono configuration. Only one
port is used.
NON-ISDN NETWORKS
PORT
LINE
(V.35/X.21)
To SW56
Network
CSU/DSU