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Cyclades-PR4000
Chapter 2 - What is in the Box 16
ISDN Switch Type (ISDN-PRI only)
Different switch vendors have different signaling protocol implementations. If you are in the US and are given a
choice of ISDN switch types, select National ISDN 2, which is intended to be the US standard switch type. Other
common and acceptable options are Custom AT&T 5ESS and Northern Telecom DMS-100. In Europe, Euro
ISDN (ETSI) is the standard ISDN switch type, but there are still some variations in use. Examples are TR6 in
Germany and VN6 in France. Australia, Japan and Korea each have their own standard switch type. Other
countries usually adopt the European standards.
Data/Voice Support
From the phone system standpoint, analog modem connections (V.34, V.90, K56 flex) are “voice” while “data”
refers to digital connections using ISDN-BRI or V.110. Lines with CAS signaling support only voice calls. Most
ISDN-PRI lines support both data and voice channels, but some lines are configured to support only voice or only
data. If given a choice, both voice and data support is preferable. If only one may be chosen, voice should be
chosen to support modem (V.34, V.90) clients and data should be chosen to support clients using ISDN-BRI or
V.110. The Cyclades-PR4000 supports both digital and analog calls and can terminate both at the same time in
the same trunk.
Phone Numbers, Hunting Groups, and Hunting Sequence
Each T1/E1 channel can have a different phone number or be organized into hunting groups with the same phone
number. In the second case, the client gets the first available line within the hunting group. The line allocation can
be done in a linear (the first available line gets a new call, from the first line to the last or vice-versa) or round-robin
fashion. ISPs usually group all lines into one hunting group so that all customers call the same phone number.
Breaking the trunk into more than one hunting group can be used to reserve a certain number of lines for different
classes of customers.
One-Way or Two-Way Service
A line can only receive calls (dial-in) or receive and generate calls (dial-out). An ISP usually only needs to receive
calls and one-way service is the recommended configuration unless you plan to support services that require dial-
out (fax servers, call back, etc.).