Telrad Digital DIGITAL FAMILY OF SYSTEMS Feature Description Addendum Manual

							Section 2: SYSTEM FEATURES 
						

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Section 3
PRIVATE NETWORKING BETWEEN 
TELEPHONE SYSTEMS
3.1 GENERAL
The DIGITAL systems’ Release 7 networking capability 
enhancement presented in this section:
• utilizes -- in addition to the existing NAP protocol -- the 
Digital Private Network Signaling System (DPNSS) and 
QSIG standard digital protocols.
• provides an expanded set of improved network-wide 
features and services;
• facilitates installation and operation of inter-system private 
networks of all sizes, comprised of both Telrad DIGITAL 
systems and telephone systems of other PBX 
manufacturers.
3.2  NETWORK ANALOG PROTOCOL (NAP)
Public networking between telephone systems described in 
previous DIGITAL system releases utilizes a Telrad proprietary 
Network Analog Protocol (NAP). Since this protocol facilitates 
the treatment of various network call communication features in 
a manner satisfactory for small networks comprised of DIGITAL 
systems only, the NAP protocol will remain in service.
System cards supporting NAP
NAP (Network Analog Protocol) operates via the following 
interfaces, represented by the respective DIGITAL system 
cabinet cards:
The availability of these cards depends on the country where 
the system is installed. • E&M • T1
• DC5 • E1 
						

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Network-wide availability of system communication 
features under NAP
As detailed in the Release 6 DIGITAL family of systems 
Operating Instructions manual, the following communication 
features can be accessed and activated between DIGITAL 
network member systems -- under NAP -- as within an 
individual DIGITAL system:
3.3  DIGITAL PRIVATE NETWORK SIGNALING SYSTEM (DPNSS)
3.3.1  What is DPNSS?
DPNSS is a British Telecommunications (BT) protocol, which is 
mandatory in the UK, can provide a good private networking 
option in other parts of Europe, the US, and Israel. 
DPNSS:
• works on a number of interface types -- 2M, 1.5M, as well as 
some V- and X-series);
• has many supplementary services defined and already 
deployed;
• allows networking with many PBXs from different 
manufacturers;
• has been selected to serve as:
•the standard DIGITAL system network protocol for 
mixed networks;
•as a proprietary protocol for private networks comprised 
of DIGITAL systems alone;
• operates only on PRI-type ISDN interfaces.
3.3.2 Interworking
With DPNSS, the DIGITAL systems can serve: 
• as a transit exchange between switches of other 
manufacturers. 
• as a gateway for trunk calls that pass to the network.
3.4  QSIG
QSIG is a standard protocol that defines signaling requirements 
at a Q reference point. QSIG protocol is a multi-vendor signaling 
system.
QSIG has been incorporated in DIGITAL systems -- for the time 
being, on a minimal level -- for basic calls only. 
• Basic messages
• Call Forward No Answer;
• Internal Page; 
• External Page;• Call Forward;
• Call Forward Busy;
• Callback;
• ImaGEN messages 
						

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3.5  PRIVATE NETWORK MEDIA AND CONNECTIVITY
A DIGITAL system will be connected to the private network in 
either of the following ways:
• digital lines running the DPNSS or QSIG protocol:
•2M    -- in ETSI domain, or
•1.5M -- in US interfaces,
• analog lines -- in the case of very small systems, where:
•a DIGITAL-system-only network is built, and 
•only features available on NAP protocol are used.
3.5.1 USA
In the USA:
• the interface for DPNSS is 1544 kbps -- 23B + D, while 
standard requirements confine the D-channel to slot 24, 
exclusively;
• in order to answer the demands of smaller systems, a partial 
span interface -- 12B + D -- will also be supported;
• on DPNSS, the DIGITAL system supports the previous set 
of features, enriched with some centralized voice mail 
functions (see Section 3.7.3, for a list of features supported);
• on NAP it is supported on E&M and T1 interfaces. The 
standard requirements confine the D-channel to slot 24, 
exclusively. There are no changes;
• NAP will be continue to be used for existing networks, to 
avoid forced upgrade to Release 7 DIGITAL systems.
3.5.2 UK
In the UK:
• the interface for DPNSS is 2048 kbps -- 30B + D;
• in order to answer the demands of smaller systems, partial 
span interfaces -- 10B + D and 20B + D, as for PRI -- will 
also be supported;
• NAP will work on the DC5 interface, as in previous releases.
3.5.3 Other countries
In most other countries:
• the interface for DPNSS in most other countries is 
2048 kbps -- 30B + D;
• NAP will work on the E1 interface, as in previous releases;
• on DPNSS, the DIGITAL system supports the previous set 
of features, enriched with some centralized voice mail 
functions (see Section 3.7.3, for a list of features supported);
• NAP will be continue to be used for existing networks, to 
avoid forced upgrade to Release 7 DIGITAL systems;
• Basic call on QSIG will be supported. 
						

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3.6 NETWORK CARDS 
Special system cabinet cards for DIGITAL systems in private 
networks have been introduced for DPNSS and QSIG. Cards 
for both protocols are prefixed by the letter N, followed by the 
number of connected channels, as follows:
• USA: N12 and N24;
• ETSI: N10, N20, and N30.
These network cards are based on the DIGITAL system PRI 
card platform:
• USA: PRI12 and 
PRI24;
•ETSI: 
PRI30 (in the UK: also PRI10 and PRI20).
A DPNSS or QSIG networking card can be switched from one 
protocol to the other by changing the firmware chip.
3.7  NETWORKING FEATURES -- SUPPLEMENTARY SERVICES
Networking features belong to two categories:
• protocol independent features;
• protocol dependent features.
3.7.1 Protocol independent features
Protocol independent features do not require inter-node 
signaling -- between the systems that comprise the private 
network.
Most important among these features are:
• uniform numbering plan;
and
• flexible translation between public and private numbering 
plans. 
These features are achieved by integrating the following 
relevant DIGITAL system capabilities with the network:
•LCR;
• system speed dialing;
• flexible DID number analysis.
There are no new requirements in Release 7 concerning this 
feature group. 
3.7.2  Protocol dependent features 
Protocol dependent features require inter-node signaling, 
between the systems that comprise the private network.
Most of these features in Release 7 DIGITAL systems will 
based on the DPNSS protocol. 
						

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3-5 3.7.3 Feature list
Table 3-1 shows the list of private network features supported 
by Release 7 DIGITAL systems, according to the protocols with 
which they comply.
* 
In the UK, the DPNSS supported features are the same features as 
supported on NAP, except for the addition of Call Back on No-
answer, Name Display, and Infinite Loop Avoidance and the 
elimination of Page, which is considered unnecessary in the UK.
3.7.4  Interprotocol feature names
Some of the names of supplementary services and system 
features vary from one protocol to another. The following name 
variations apply to Release 7 features.Table 3-1 DIGITAL System Release 7 Private Network 
Features
feature name
    
    NAP
 
 DPNSS* 
   
   QSIG
Basic Call Y Y Y
Call Back on Busy Y Y -
Call Back on No Answer - Y -
Call Forward (Call Diversion) Y Y -
Calling Line Identification Presentation (CLIP) Y Y Y
Centralized 
voice mailCall Forward to Mailbox Y Y -
Call Record - Y -
Message LED Y Y -
Message Retrieval from Mailbox Y Y -
Voice Mail Screens - Y -
Voice Memo Y Y -
Conference Add-on Y Y -
Hold + Transfer + Conference (3-party) Y Y Y
Infinite Loop Avoidance - Y Y
Interworking for Basic Call Services -  Y Y
Message Y Y -
Name Display - Y -
Page Y Y -
Transit Capability - Y -
Trunk Optimization Y Y - 
						

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CBWF
Call Back when Free (CBWF) is also known as:
• Call Back on Busy (CCB)  -- DPNSS;
• Completion of Calls to Busy Subscribers (CCBS)  -- QSIG.
CBNU
Call Back when Next Used (CBNU) is also known as:
• Call Back on No Answer (CCNA)  -- DPNSS;
• Completion of Calls on No Reply (CCNR)  -- QSIG.
CF
Call Forward (CF) is also known as:
• Call Diversion (CD)  -- DPNSS;
• Call Forwarding Unconditional (CFU)  -- QSIG. 
						

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