Section 5 ISDN
89
Directory Numbers (DNs)
Directory Numbers, or DNs for short, are the 7 digit telephone numbers assigned to the
ISDN line (as would typically found in the telephone
directory
). You may be assigned
one or two, depending upon the line configuration. In the case where you have two
active ISDN B channels, you will usually have two DNs (but not always). However, the
"physical" channels are independent from the "logical" numbers. A call coming in on
the second number will be assigned the first physical B channel, if it is not already
occupied. Therefore, there must be some way for the Zephyr to sort out which call goes
to which channel/line. The DN is used for this function.
When a call rings in, it contains set- up information which includes the DN that was
dialed by the originating caller. The last seven digits are matched with the DNs
programmed into the Zephyr and the proper assignment is made. Therefore, problems
with Directory Numbers will virtually always be difficulties related to receiving calls.
DEEP TECH NOTE!
The intention of the SPID is to allow the Telco equipment to
automatically support different terminal equipment feature
requirements by sensing different SPIDs from each user
terminal sharing a BRI circuit. For instance, multibutton
phones could retain function assignments when moving from
line to line. In this case, the line number would probably not be
used as the SPID. Or, to allow a variety of different types of
equipment, with different service requirements, to share one
ISDN line. None of this matters with our application, but we
must enter the SPIDs nevertheless.
CURIOSITY NOTE!
There is hope on the horizon that SPID difficulties will become
a thing of the past. For one thing, the Telcos are beginning to
standardize on area code+phone 0101 for SPIDs on
National ISDN lines.
Standards for future versions of National ISDN will include
automatic SPID assignment/selection and non-initializing
terminals which would be allowed to operate without a SPID,
albeit with only basic functionality.
Telos Systems is monitoring these developments carefully.
ISDN TIP!
However, it is not usually necessary to explicitly enter them, as
they are almost always contained within the SPID, and the
Zephyr is smart enough to look there first. The only time it is
required to enter the DN is in the very rare case that the seven
digits of the DN are not included somewhere within the SPID.
When DNs are required, only the last seven digits (no area
code) need be entered.
Summary of Contents for Zephyr
Page 13: ...Table of Contents 13 SECTION 1 QUICK RESULTS ...
Page 26: ...Section 2 INTRODUCTION 26 This page intentially left blank ...
Page 27: ...Section 2 INTRODUCTION 27 SECTION 2 INTRODUCTION ...
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Page 39: ...39 SECTION 3 ZEPHYR AT A GLANCE ...
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Page 53: ...Section 4 INSTALLATION BASIC OP 53 SECTION 4 INSTALLATION BASIC OPERATION ...
Page 84: ...Section 4 INSTALLATION BASIC OPERATION 84 ...
Page 85: ...Section 5 ISDN 85 SECTION 5 ISDN ...
Page 105: ...Section 6 NON ISDN NETWORKS 105 SECTION 7 AUDIO CODING ...
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Page 119: ...Section 8 DETAILED MENU REFERENCE 119 SECTION 8 DETAILED MENU REFERENCE ...
Page 157: ...Section 9 REMOTE CONTROL 157 SECTION 9 REMOTE CONTROL ...
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Page 177: ...Section 10 ADVANCED PROBLEM SOLVING 177 SECTION 10 ADVANCED PROBLEM SOLVING ...
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Page 197: ...Section 11 TECHNICAL INFORMATION 197 SECTION 11 DETAILED TECHNICAL INFORMATION ...
Page 219: ...Section 12 SCHEMATICS 219 SECTION 12 SCHEMATICS ...
Page 221: ...Section 13 MANUFACTURER S DATA SHEETS 221 SECTION 13 MANUFACTURER S DATA SHEETS ...
Page 223: ...Section 14 SPECIFICATIONS WARRANTY 223 SECTION 14 SPECIFICATIONS AND WARRANTY ...
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Page 229: ...Section 15 APPENDICES 229 SECTION 15 APPENDICES ...