PHS MoU Document
B-IW2.00-02-TS
Title: Public Personal Handy-Phone System : Network Interworking
between a Public PHS Network and an ISDN, and between
Public PHS Networks
Version: 02
Date: July 31, 1998
PHS MoU Classification: Unrestricted
List of contents:

1.
2.

Introduction
Scope
3.
4.
5.

Required information and information handling
Description of Public PHS network-public PHS network/ISDN interworking
configurations
Interworking functions

Annex A Glossary and Abbreviations

Number of pages: 10

PHS MoU Group
c/o Association of Radio Industries and Businesses (ARIB)
14F, Nittochi Bldg., 4-1, Kasumigaseki 1-choume, Chiyoda-ku, Tokyo 100, Japan
TEL +81-3-5510-8599 FAX +81-3-3592-1103© PHS MoU Group1998

PHS MoU Document
B-IW2.00-02-TS
VersionHistory of Revised Versions
Date
Outline01

Dec. 19, 1997 Established

02

July 31, 1998 64 kbit/s unrestricted data bearer service isadded in section 5.

B-IW2.00-02-TS

Public Personal Handy-Phone System:
Network Interworking between a Public PHS Network and an ISDN,and between Public PHS Networks< Summary >1. Relationship with International Standards
This specification specifies interworking between a public PHS network and an ISDN, and between
public PHS networks based on ITU-T Recommendation I.520 which specifies ISDN-ISDN
interworking arrangements.
2. Differences to/from International Recommendations(1) Network model and terminology
ITU-T Recommendation I.520 specifies interworking where both interworking networks are ISDNs.
This specification changes this model such that one of the interworking networks is a public PHS
network and the other network is either a public PHS network or an ISDN. The differences of modeland terminology from ITU-T Recommendation I.520 are summarized in Table Summary-1/B-IW2.00.
(2) Specifications
The differences of specifications from ITU-T Recommendation I.520 are summarized in Table
Summary-2/B-IW2.00.
The following specifications have been deleted from ITU-T Recommendation I.520:- Packet mode bearer service;- Additional packet mode bearer service;- Transit network selection information element in IF2 and IF3;
- Key pad information element for overlap sending/receiving;- Alternate speech/64 kbit/s unrestricted bearer service;- Multi-use bearer service;- Restricted 64 kbit/s transfer capability.
3. References
ITU-T Recommendations:
PHS MoU Documents:

I.5xx series
B-IF2.xx, B-IF3.xx, B-IWx.xx series

4. Items for Further Study
None

B-IW2.00-02-TS(1)

Table Summary-1/B-IW2.00 Differences of model and Terminology from ITU-T
Recommendation I.520
Item
I.520
Interworking
Both sides of interworking networks
network model are ISDNs.
Network
configuration
figureBoth networks are ISDNs.

Terminology

ISDN - in a context of service
ISDN(s) - in a context ofinterworking
ISDN-ISDN
64 kbit/s unrestricted data
Nx, KxISDNcsReference

ITU-T Recommendations
I.510,
I.530,
I.324 (for Nx, Kx definitions),
Q.763,
Q.931(2) B-IW2.00-02-TS

This specification
One of the interworking networks is a
public PHS network, and the other one iseither a public PHS network or an ISDN.
Left side network is a public PHS networkand right side network is either a public
PHS network or an ISDN.
(specified as “Public PHS network/ISDN”)
public PHS network
public PHS network and public PHS
network/ISDN
public PHS networkpublic PHS network/ISDN
32 kbit/s unrestricted data and 64 kbit/s
unrestricted data
IF3 (Nx), IF3 (Kx)public PHS network (circuit switched)/
ISDN (circuit switched)
PHS MoU Documents
B-IW0.01,
B-IW3.00,
B-IW0.01,
B-IF3.33,
B-IF2.02

Table Summary-2/B-IW2.00 Differences of specifications from ITU-T
Recommendation I.520
Section
3. Required information and information
handling
4.1.2.2 User-to-user signalling services
4.2 ISDN-ISDN interface where both ISDNs
provide X.31 case B based packet modebearer services
4.3 ISDN-ISDN interface where a circuit modebearer service is provided by one ISDN toaccess either a PSPDN, or a PH and an X.31
case B packet mode bearer service provided
by another ISDN
4.5 ISDN-ISDN interface for additional packet
mode bearer services
4.6 ISDN-ISDN interface where an X.31 case B
based packet mode bearer service is provided
on one ISDN and an additional packet modebearer services is requested on another ISDN
4.7 ISDN-ISDN interface for circuit mode to
additional packet mode service
5.1 Echo control processing

5.4 Compatibility checking between end users ofdifferent ISDNs
6. Functional interworking requirements for datatransmission services
7. Reference
Annex A GLOSSARY and ABBREVIATIONSAppendix I ISDN connections involving
restricted 64 kbit/s transfer
capability

Differences- Descriptions including Table 3/I.520 relating topacket mode bearer service are deleted.
- Transit network selection in Table 1/I.520 ischanged to unnecessary.
- Key pad for called party number in category ii
of Table 1/I.520 is deleted.

- This section relating to packet mode bearer
service is not included.

- This section relating to additional packet modebearer service is not included.
- This section relating to packet mode bearer
service and additional packet modebearer service is not included.
- This section relating to additional packet modebearer service is not included.
- Alternate speech/64 kbit/s unrestricted bearer
service is deleted.
- Multi-use bearer service is deleted.
- 32 kbit/s unrestricted bearer service and 64
kbit/s unrestricted bearer service are described
separately.
- IWF treatment on LLC information is described.
- This section relating to additional packet modebearer service is not included.
- Reference is included in summary.
- Annex A is added.
- This appendix relating to restricted 64 kbit/s
transfer capability is not included.

B-IW2.00-02-TS(3)

B-IW2.00-02-TS
Public Personal Handy-Phone System:
Network Interworking between a Public PHS Network and an ISDN,and between Public PHS Networks

Contents

1. Introduction .........................................................................................................................................

1

2. Scope ....................................................................................................................................................

1

3. Required information and information handling .................................................................................

1

4. Description of Public PHS network-public PHS network/ISDN interworking configurations ..........

3

4.1 Public PHS network-public PHS network/ISDN interface where circuit mode bearer
services are provided by both public PHS networks/ISDNs .............................................................

3•4.2 Public PHS network-public PHS network/ISDN interworking via a transit network ....................

4

5. Interworking functions ........................................................................................................................

4

5.1 Echo control processing and speech processing ..............................................................................

4

5.2 Generation of in-band tones and announcements for speech and 3.1 kHz audio bearer
services ..............................................................................................................................................

5

5.3 Call negotiation between a public PHS network and a public PHS network/ISDN .......................

6

5.4 Compatibility checking between end users of different public PHS networks/ISDNs ...................

7

Annex A GLOSSARY and ABBREVIATIONS...................................................................................

9

B-IW2.00-02-TSi

1. Introduction
The number of public PHS networks existing in the world is increasing and public PHS networks
must be introduced having inter-connectivity with existing ISDNs and other public PHS networks.
Therefore public PHS network-ISDN as well as public PHS network-public PHS network interfaces
should be standardized to facilitate the interworking between ISDNs and to extend connectivity
world-wide.
2. Scope
The purposes of this document are1) to identify the general arrangements for public PHS network-public PHS network/ISDN•interworking, and2) to define the functions and other requirements for the public PHS network-public PHS•network/ISDN interface.
B-IW0.01 defines the reference point between two interconnected public PHS networks to be the IF3(Nx) reference point. This Specification document identifies other Specification document whichshould be applied to the IF3 (Nx) reference point and clarifies the functions and requirements forinterworking at the IF3 (Nx) reference point.
3. Required information and information handling
Figure 3-1/B-IW2.00 illustrates the general configuration for interworking between a public PHS
network and a public PHS network/ISDN. The information given in Tables 3-1/B-IW2.00 and 3-2/BIW2.00 when required, has to be carried by Signalling System No.7 (SS No.7) ISUP and is handled at
the IWF in one of the following ways:i) information is terminated at the IWF and is not transferred to other public PHS•networks/ISDNs;ii) information is interpreted at the IWF and is transferred to other public PHS
networks/ISDNs;iii) information is transferred through the IWF transparently;iv) information is newly generated at the IWF.
Tables 3-1/B-IW2.00 and 3-2/B-IW2.00 also show the classification of information into the above
four categories for circuit mode bearer services and circuit mode supplementary services respectively.

PublicPS

Public PHS
Network

IWF

IWF
IF3(Nx)

Public PHS
Network/ISDN

PublicPS

Figure 3-1/B-IW2.00 General configuration for interworking between public PHS
network and public PHS network/ISDN

B-IW2.00-02-TS 1

Table 3-1/B-IW2.00 Information required for IWF between public PHS network andpublic PHS network/ISDN for circuit mode bearer service
Categoryiii

Required information
First transit network
subsequent to IWF
Called party number(Note 1)
Calling party's category(Note 2)
Bearer capability

B-IF3.33 (Q.763)
parameter name
(Unnecessary)

Called party number

Called party number/
Subsequent number
Calling party's category(Unnecessary)
Bearer capability

Call indicators (Note 3)(Unnecessary)

Use of satellite (Note 4)(Unnecessary)iii
Calling party number(Note 8) Subaddress
Calling party's category
Terminal compatibility(Note 5)User-to-user signallingiv

B-IF2.02 (Q.931)
information element(Unnecessary)

Calling party number
Subaddress(Unnecessary)
Low layer compatibility
High layer compatibility
Use-to-user information
element
Cause(Unnecessary)
Cause(Unnecessary)

Cause
ChargeCause for interworking
Charging information(Note 6)
Change of service (Note 7) (Should be defined)

Transmission medium
requirements
User service information
Forward call indicators
Backward call indicators
Nature of connection
indicators
Calling party number
Access transport
Calling party's category
Access transport
Use-to-user information
Cause indicator
Charge information
Cause indicator
Charge information(Should be defined)

NOTES
1. For charging use.
2. For discrimination of priority call/ordinary call.
3. Those indicators are used to identify:a) international incoming call;b) available end-to-end signalling system;c) charged call/noncharged call.
4. When a satellite circuit is employed for an interworking call at the interworking point, thisinformation is processed at the IWF. If a satellite circuit is not employed for a call, thisinformation is transferred through the IWF transparently.
5. There may be cases where the terminal compatibility information is processed (see 5.4).
6. This information is used only when access charging is necessary.
7. All public PHS networks/ISDNs do not necessarily provide identical services (or connection
types). When a change of services occurs at the IWF, the network should send the indication
for change of services and may solicit acceptance of change of services to a calling user incertain cases (see 5.3.1).
8. The information in this category is transferred through the IWF transparently.

2

B-IW2.00-02-TS

Table 3-2/B-IW2.00 Information required for IWF between public PHS network andpublic PHS network/ISDN for circuit mode supplementary services
Categoryii

iii

Required information

B-IF2.02 (Q.931)
information element
Supplementary service
Network specific facility
requestKey pad facility
Feature activation
Feature indication
Progress indicator
Progress indicator
Suspend/Resume indicator Notification indicator

B-IF3.33 (Q.763)
parameter name(Should be defined)

Access transport
Suspend/Resume indicator

Additional information required specifically for OAM (Operational, Administrative and Maintenance)
functions is for further study.
4. Description of public PHS network-public PHS network/ISDN interworking
configurations
4.1 Public PHS network-public PHS network/ISDN interface where circuit mode bearer
services are provided by both networks
See Figure 4-1/B-IW2.00.

Public PHS network(circuit switched)

IF3 (Nx)

Public PHS network/ISDN(circuit switched)

SS No.7

Figure 4-1/B-IW2.00 Public PHS network (circuit switched) interworking with public
PHS network/ISDN (circuit switched)
4.1.1 Bearer services
Individual bearer service categories are defined in the I.230-Series Recommendations.
Layer 1 interworking specifications are recommended in Recommendation I.511. Layers 2 and 3 in
the U-plane are passed transparently.
4.1.2 Supplementary services
4.1.2.1 Other than user-to-user signalling
For supplementary services other than use-to-user signalling, call control information is transferred
via Signalling System No. 7 across the IF3 (Nx) reference point. The interface for user informationtransfer is not different from that of basic bearer services.

B-IW2.00-02-TS 3

4.1.2.2 User-to-user signalling services
There are two methods of transferring user-to-user signalling. One is transfer of user-to-user
signalling within B-IF2.02 call control messages which have been mapped into Signalling System No.
7 messages and then are conveyed via the Signalling System No. 7 network. The other is transfer ofuser-to-user signalling within stand alone USER INFO messages (which have been mapped into
Signalling System No. 7 messages and then are conveyed via the Signalling System No. 7 network).
In the case where user-to-user signalling is transferred via Signalling System No. 7 networks in both apublic PHS network and a public PHS network/ISDN or at least in one of the networks, the Signalling
System No. 7 protocol should be applied to the internetwork interface for user-to-user signalling.
4.1.3 Signalling System No. 7 for the control of circuit mode service at the IF3 (Nx)reference point
For the control of circuit mode services in the long term, Signalling System No. 7 with ISUP will be
used at the IF3 (Nx) reference point.
4.2 Public PHS network-public PHS network/ISDN interworking via a transit network
Public PHS network-public PHS network/ISDN interworking via a transit network (see Figure 4-2/BIW2.00) may be useful configuration in the short term for extending specific public PHS network
services on an end-to-end basis. Special transmission, switching and signalling capabilities may haveto be deployed in the transit network to ensure that the specific public PHS network service isavailable end-to-end.

IF3 (Kx)

IF3 (Kx)
PublicPS

Public PHS
Network

Transit network

Public PHS
Network/ISDN

PublicPS

Figure 4-2/B-IW2.00 Interworking between public PHS network and public PHS
network/ISDN via a transit network

The detailed interworking functions and interfaces for this configuration are for further study.
5. Interworking functions
Interworking functions commonly employed for various types of interworking are described in BIW0.01. The interworking functions specific to public PHS network-public PHS network/ISDN
interworking are described here.
5.1 Echo control processing and speech processing
Table 5-1/B-IW2.00 shows the permitted relationship between circuit mode bearer services andvarious forms of speech processing functionality. These speech processing functions include digital

4

B-IW2.00-02-TS

speech interpolation (DSI), low rate encoding (LRE) and digital circuit multiplication (DCM).
Depending upon the particular relationship to the circuit mode bearer services, these processing
functions are specified as essential, optional, prohibited or functionally disabled.
For a speech, 3.1 kHz audio, 32 kbit/s unrestricted, or 64 kbit/s unrestricted call within a public PHS
network, appropriate network control is required to ensure that the relationship shown within Table 51/B-IW2.00 is realized. An example of this control might be routing (to exclude or include a function)or out-band signalling (to disable a function). Further, it is to be noted that a disabling tone (seeRecommendation V.25 and B-IW3.00) may be used to functionally remove echo control devices on a
3.1 kHz audio bearer service connection.
For a call which involves communication through different public PHS networks, the network
information regarding control of these functions needs to be extended across the public PHS networkpublic PHS network/ISDN internetwork interfaces. This information transfer is realized between theexchanges in interworking public PHS network-public PHS network/ISDN by means of
1)

the Signalling System No. 7 ISUP bearer capability information element, and2)

the use of disabling tone (see Recommendation V.25 and B-IW3.00) by terminals, inthe case of a 3.1 kHz audio bearer service.

The control of speech processing functions (DCM, A-P law conversion, echo control, etc.) byexchanges isa)

not needed when a disabling tone (see Recommendation V.25 and B-IW3.00) is used,in conjunction with the 3.1 kHz audio bearer service by a terminal(s), andb)

to be implemented using out-band call processes (currently under study) when needed.

5.2 Generation of in-band tones and announcements for speech and 3.1 kHz audio bearer
services
NOTE - This function is also necessary for a call within one public PHS network, which
does not involve network interworking nor internal public PHS network interworking.
5.2.1 Unsuccessful call delivery
The point of call failure (i.e. the point at which the connection cannot proceed further) should
generate the appropriate out-band clearing message toward the calling exchange. In response to thismessage, the calling exchange should send the appropriate out-band message to the calling user.
However, for speech and 3.1 kHz audio bearer services, the network must be capable of generating
the appropriate in-band tones or announcements. In this case, the clearing message should not be sent
prior to the completion of the announcements.
5.2.2 Successful call delivery
For speech and 3.1 kHz audio bearer services, the terminating exchange should generate in-band ringback tone towards the calling user upon successful delivery of the call.

B-IW2.00-02-TS 5

Table 5-1/B-IW2.00 Relationship between speech processing and bearer services withina public PHS network and for a public PHS network-public PHS
network/ISDN interworking
Bearer service
Speech processing
functions

1

2

3

4

Speech3.1 kHz32 kbit/s
unrestricted

64 kbit/s
unrestricted

FD
FD
FD
FD
FD g)

FD
FD
FD
FD
FD h)

P

P

audio a)Echo control b)
A-P law conversion e)
DSI
LRE
DCM
Analogue facilities

E c) d)EOOOO

E c) d)
E
O f)
O f)
O f)
O f)

E
Essential
O
Optional
P
Prohibited
FD
Functionally disabled
DSI
Digital speech interpolation
LRE
Low rate encoding (e.g. Recommendation G.721)
DCM
Digital circuit multiplication employing LRE and DSI and having controllable flexibility inmodes of operation.
a) For the 3.1 kHz audio bearer service, echo control is included in the connection at the time of call
set-up. It is disabled for the transmission of voice-band data by use of the disabling tone (seeRecommendation V.25 and B-IW3.00).
b) Echo control needs to be disabled when continuity check is performed.
c) Although echo control may not be required in public PHS network-public PHS network/ISDN
interworking for digital telephones (for further study), its inclusion for possible internetworking
reasons for the speech bearer service is essential (see also B-IW3.00).
d) The necessity for network or terminal provided echo control in 4-wire end-to-end speechconnections is for further study.
e) The IWF converting A-P laws should also make the necessary bit translation in the bearercapability information element to indicate the law used.
f) The network may include signal processing techniques provided they are appropriately modified
or functionally removed prior to information transfer.
g) The 32 kbit/s transparent capability will be invoked, subject to the available transmission
capacity, by the adjoining exchange over a dedicated out-band signalling system.
The 64 kbit/s transparent capability will be invoked, subject to the available transmission capacity, by
the adjoining exchange over a dedicated out-band signalling system.
NOTE – The bearer services in columns 1, 2, 3 and 4 of the table permit control of speech processing
devices only at call set-up as required for the particular bearer service requested.

5.3 Call negotiation between a public PHS network and a public PHS network/ISDN

6

B-IW2.00-02-TS

There are two aspects of call negotiation between a public PHS network and a public PHS
network/ISDN: service agreement and connection agreement.
5.3.1 Service agreement between a public PHS network and a public PHS network/ISDN
Service agreement between a public PHS network and a public PHS network/ISDN is defined as
established compatibility between the two networks on a requested service. The service agreement
does not necessarily occur on a call-by-call basis, but in a pre-determined way which has been agreed
by bilateral negotiation between the two networks. If the service agreement is established, connection
agreement then begins between the two networks.
If the service agreement is not established, procedures are for further study, including the following
four alternatives. Additionally, the impact of these alternatives on user-to-network protocols orinternetwork protocols is for further study.
1)

The call may be established without the service compatibility (e.g. in the case of a
supplementary service request).

2)

The call may be cleared.

3)

Either of the two networks may negotiate with the originating user to change orabandon the user’s service request.

4)

Another alternative may be selected from the originating user’s service profile.

5.3.2 Connection agreement between a public PHS network and a public PHS network/ISDN
Connection agreement between a public PHS network and a public PHS network/ISDN is defined as
negotiation on the connection element between the two networks. Connection agreement is required
when the connection elements employed in each public PHS network/ISDN are different, even if
service agreement exists. The use of call progress indicators for this purpose is for further study.
In a speech bearer service, the objects for connection agreement might be the use of one of thefollowing: UDI (unrestricted digital information), satellite circuits, DSI circuits, the difference of
PCM coding rules, circuit selection between digital networks having different hierarchical structures,etc. Parameter exchange, if required, are executed by the two networks.
The connection agreement does not necessarily occur on a call-by-call basis, but in a pre-determined
way which has been established by other Recommendations (e.g. Recommendation G.802 forinterworking between hierarchies and Recommendation G.711 for A-P law conversion) or agreed
between a public PHS network and a public PHS network/ISDN.
5.4 Compatibility checking between end users of different public PHS networks/ISDNs
When the connection path between two terminals on different public PHS networks/ISDNs isestablished, low layer compatibility (LLC), high layer compatibility (HLC) or user definedcompatibility may be examined on an end-to-end basis.

B-IW2.00-02-TS 7

Compatibility checking items between end users are as follows:1)

Low layer compatibility

LLC information would normally be used for user-to-user call negotiation and would be
passed transparently through the networks. The IWF may, where required, examine andact on LLC information (see 2.2.1.3/I.515) in the cases where the LLC checking lists(see B-IF2.02) employed by the two relevant networks are different.
LLC information as well as Bearer capability information is used by IWFs in public PHS
networks to select either 32 kbit/s or 64 kbit/s unrestricted data bearer service of IF1 forincoming data calls to public PSs. The IWFs in public PHS networks may modify the
LLC information in some cases (see B-IF1.01).
2)

High layer compatibility
The HLC is to be conveyed transparently and the networks need not operate on it. The
examination and action on HLC information by the IWF is for further study, in the casewhere the HLC checking lists employed by the two relevant networks are different.

3)

User defined compatibility checking
User defined compatibility checking is the user responsibility. The network does notparticipate in this compatibility checking.

8

B-IW2.00-02-TS

Annex A GLOSSARY and ABBREVIATIONSThis annex forms an integral part of this document.
GLOSSARY***A******B******C******D******E******F******G******H******I***
IF3(Kx)PHS MoU
The network interworking reference point is the IF3(Kx) reference point when the network directlyinterconnected to the public PHS network is a non-ISDN.
IF3(Nx)PHS MoU
The network interworking reference point is the IF3(Nx) reference point when the network directlyinterconnected to the public PHS network is a public PHS network or an ISDN.
***J******K******L******M******N******O******P******Q******R******S******T******U******V******W******X******Y******Z***

B-IW2.00-02-TS 9

ABBREVIATIONS
DCM
DSI
HLC
ISUP
IWF
LLC
LRE
PCM
UDI

10

Digital Circuit Multiplication
Digital Speech Interpolation
High Layer Compatibility
ISDN User Part
InterWorking Function
Low Layer Compatibility
Low Rate Encoding
Pulse Code Modulation
Unrestricted Digital Information

B-IW2.00-02-TS