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Chapter 6

Australian P2 Protocol

6.1 Introduction

6.2 Capability Mask

6.3 Signaling Overview

6.4 Parameters

: 6.4.1 Editable Parameters
: 6.4.2 Non-editable Parameters

6.5 Special TCP Behavior

: 6.5.1 Inbound Calls: Retrieving Digits All at Once
: 6.5.2 Inbound Calls: Receiving Digits One at a Time
: 6.5.3 Billing Pulses

6.1 Introduction

This chapter describes the Australian P2 (AP2) signaling protocol and TCP parameters. It provides the following information: Overview of the signaling performed by the AP2 protocol. AP2 TCP parameters. Operations that are specific to the AP2 TCP within the framework of Natural Call Control.
The AP2 TCP implements the specifications of the Telstra CAS protocol P2. This protocol is widely used in Australia to connect PBXs to the PSTN, for Telstra and other carriers.

6.2 Capability Mask

With the NCC service, an application can call nccQueryCapability to determine the capabilities of a protocol. nccQueryCapability returns a capabilitymask.
For information about the capabilities supported for NMS CAS protocols with NCC call control, refer to Appendix A.

6.3 Signaling Overview

The Australian P2 protocol uses the line signaling scheme specified by the CCITT for the MFC-R2 protocol (Recommendation Q.421). Two bits are used for each direction. Thus the signaling channels supporting the line signaling of these protocols are referred to as A_fand B_f in the forward direction, and A_b and B_b in the backward direction. The forward channel indicates the condition of the outbound switch equipment and reflects the condition of the calling party's line. The backward channel indicates the condition of the called party's line (the inbound equipment). The C and D bits are never used. Their value is fixed at 0 and 1 respectively.
The following table illustrates the signaling states of a typical call: State Outbound A_fB_f Direction Inbound A_bB_b Idle 10 10 Seizure 00 10 Seizure Acknowledged 00 11 The outbound side sends the address information using in-band DTMF tones or decadic pulses. If decadic pulses are used, the A_f bit pulses on and off to signal the address digits. If, after all the address information has been transferred, the inbound side accepts the call, it plays a ring tone on the line, and then signals that the call has been answered by setting the A_b bit to 0. Ringing 00 11 Answer - conversation state 00 01 If the inbound side rejects the call, the outbound side clears forward by setting the A_f bit to 1. The inbound side goes back to idle by setting the B_b bit to 0. Clear forward 10 11 Idle 10 10 During conversation the outbound protocol can receive billing pulses to signal that a unit of cost has been billed to the call. The bit used to carry a billing pulse depends on national specifications. Answer - conversation state 00 01 Billing pulses 00 11 or 00 Answer - conversation state 00 01 Depending on which side hangs up the call first, either a clear back signal or a clear forward signal is generated. Depending on national specifications, there might be a period of time during which the inbound side holds a release guard state, which is the same as clear back but happens when the outbound side is already in the idle state. Idle follows. Inbound hangs up first: Clear back 00 11 Clear forward 10 11 Idle 10 10 Outbound hangs up first: Clear forward 10 01 Release guard 10 11 Idle 10 10
The AP2 protocol uses either in-band DTMF tones or out-of-band decadic pulses to transfer register signaling information.
This protocol only transfers DID (direct inward dialing - the called address) information. To do this, the outbound side sends either a stream of DTMF tones or a sequence of decadic pulses to the inbound side, then considers the dialing done and waits for some confirmation from the inbound side. This register signaling technique, in which the outbound side has no acknowledgment from the inbound side until the dialing is finished, is called digit spill.

State	Outbound A_fB_f	Inbound A_bB_b
Idle	10	10
Seizure	00	10
Seizure Acknowledged	00	11
The outbound side sends the address information using in-band DTMF tones or decadic pulses. If decadic pulses are used, the A_f bit pulses on and off to signal the address digits. If, after all the address information has been transferred, the inbound side accepts the call, it plays a ring tone on the line, and then signals that the call has been answered by setting the A_b bit to 0.
Ringing	00	11
Answer - conversation state	00	01
If the inbound side rejects the call, the outbound side clears forward by setting the A_f bit to 1. The inbound side goes back to idle by setting the B_b bit to 0.
Clear forward	10	11
Idle	10	10
During conversation the outbound protocol can receive billing pulses to signal that a unit of cost has been billed to the call. The bit used to carry a billing pulse depends on national specifications.
Answer - conversation state	00	01
Billing pulses	00	11 or 00
Answer - conversation state	00	01
Depending on which side hangs up the call first, either a clear back signal or a clear forward signal is generated. Depending on national specifications, there might be a period of time during which the inbound side holds a release guard state, which is the same as clear back but happens when the outbound side is already in the idle state. Idle follows.
Inbound hangs up first: Clear back	00	11
Clear forward	10	11
Idle	10	10
Outbound hangs up first: Clear forward	10	01
Release guard	10	11
Idle	10	10

6.4 Parameters

The AP2 TCP is programmed by the parameters described in the following tables to implement the specifications of the supported countries and network operators. These parameters are stored within the parameter category NCC.X.ADI_AP2.
Parameters in this category fall into two groups: Parameters that program TCP/host interaction, or that act on features not regulated or that can change from switch to switch within the same network. You can freely edit these parameters to suit your implementation. Parameters that are signaling-specific: changing their values invalidates approvals for the board, and may cause the board to malfunction. These parameters are described here for reference purposes only.

6.4.1 Editable Parameters

The following table describes NCC.X.ADI_AP2 parameters (within the parameter category NCC.X.ADI_AP2) that you may modify. Also listed are the equivalent ADI.AP2 parameters, to assist with migration from ADI to NCC. NCC Field Name ADI Field Name Unit Default Description digitnumber digitnumber count 7 Inbound: specifies number of incoming digits to expect waitingplaybusy optionflags (bit 0) mask 0x0 This parameter and the waitingplayreorder parameter specify what to play as cleardown tone (the tone the TCP plays when an inbound call is released and the calling party has not hung up yet). If this parameter is 1, the busy tone is used as the cleardown tone. If neither of the parameters is set, the TCP remains silent. waitingplayreorder optionflags (bit 1) mask 0x1 This parameter and the waitingplaybusy parameter specify what to play as cleardown tone (the tone the TCP plays when an inbound call is released and the calling party has not hung up yet). If this parameter is 1, the fast busy (reorder) tone is used as the cleardown tone. If neither of the parameters is set, the TCP remains silent. trunkdirection optionflags (bits 2 and 8) mask 0x0 Determine trunk direction: 0 bidirectional 1 Inbound only (no calls can be placed on it) 2 Outbound only (no calls can be received on it) detectnetworkaudio optionflags (bit 5) mask 0x0 Setting this parameter to 1 forces the TCP to perform call progress when all digits have been delivered to the network in an outbound call, even for protocols that give a positive indication of the state of the call. The default value is 0. This will not start call progress detection if the user sets the connectmask to connect on SIGNAL. This value saves DSP resources. lastdtmf optionflags (bits 13 - 18) mask 0x0 These bits define the ST tone: the last received tone that outbound sends. 0 = ignored.

NCC Field Name	ADI Field Name	Unit	Default	Description
digitnumber	digitnumber	count	7	Inbound: specifies number of incoming digits to expect
waitingplaybusy	optionflags (bit 0)	mask	0x0	This parameter and the waitingplayreorder parameter specify what to play as cleardown tone (the tone the TCP plays when an inbound call is released and the calling party has not hung up yet). If this parameter is 1, the busy tone is used as the cleardown tone. If neither of the parameters is set, the TCP remains silent.
waitingplayreorder	optionflags (bit 1)	mask	0x1	This parameter and the waitingplaybusy parameter specify what to play as cleardown tone (the tone the TCP plays when an inbound call is released and the calling party has not hung up yet). If this parameter is 1, the fast busy (reorder) tone is used as the cleardown tone. If neither of the parameters is set, the TCP remains silent.
trunkdirection	optionflags (bits 2 and 8)	mask	0x0	Determine trunk direction: 0 bidirectional 1 Inbound only (no calls can be placed on it) 2 Outbound only (no calls can be received on it)
detectnetworkaudio	optionflags (bit 5)	mask	0x0	Setting this parameter to 1 forces the TCP to perform call progress when all digits have been delivered to the network in an outbound call, even for protocols that give a positive indication of the state of the call. The default value is 0. This will not start call progress detection if the user sets the connectmask to connect on SIGNAL. This value saves DSP resources.
lastdtmf	optionflags (bits 13 - 18)	mask	0x0	These bits define the ST tone: the last received tone that outbound sends. 0 = ignored.

6.4.2 Non-editable Parameters

The following NCC.X.ADI_AP2 parameters are country or network-specific, and cannot be modified. Also listed are the equivalent ADI.AP2 parameters, to assist with migration from ADI to NCC.

Caution:

Most of the parameters that follow are signaling-specific: changing their value will invalidate any approval certificate for the used board, and may cause the board to malfunction. These parameters are described here for reference purposes only.

NCC Field Name

ADI Field Name

Type/Unit

Default

Description

seizureacktime

seizureacktime

ms

10000

Outbound: Specifies time to wait for seizure acknowledgment after seizing the line.

seizurewaittime

seizurewaittime

ms

200

Outbound: Specifies the time to wait to be seized in a two-way trunk, after the TCP seized the line.

answerwaittime

answerwaittime

count

90

Outbound: Specifies the maximum time for the protocol to wait after the call accepted indication until the phone is answered (seconds).

acceptwaittime

acceptwaittime

ms

20000

Outbound: Specifies the maximum time for the protocol to wait after dialing before being notified that either the call has been accepted and the phone is ringing, or that the call has been rejected.

digitspilltime

digitspilltime

ms

20000

Inbound: Specifies the total time the dialing process is allowed to take.

bitqualtime

bitqualtime

ms

20

Specifies the qualification time for bit changes.

interdigitreceivetime

interdigitreceivetime

ms

5000

Inbound: While receiving decadic pulses, if the number of expected incoming digits is not known, this parameter specifies the time between two trains of pulses to conclude that the incoming dial string is finished.

winktime

winktime

ms

150

Inbound: Specifies the duration of an inbound wink. Depending on the target country, the wink has a different meaning and occurs at different phases of call setup.

toneontime

toneontime

ms

80

Specifies the time a DTMF tone should be ON while dialing.

toneofftime

toneofftime

ms

80

Specifies the time a DTMF tone should be OFF while dialing.

pulseontime

pulseontime

ms

50

Specifies the time a pulse should be ON while dialing with decadic pulses.

pulseofftime

pulseofftime

ms

50

Specifies the time a pulse should be OFF while dialing with decadic pulses.

hightoneamplitude

hightoneamplitude

IDU

352

Specifies the amplitude of the higher frequency of the DTMF tones while dialing.

lowtoneamplitude

lowtoneamplitude

IDU

440

Specifies the amplitude of the lower frequency of the DTMF tones while dialing.

interdigitsendtime

interdigitsendtime

ms

700

Outbound: Specifies the time between two trains of pulses while dialing with decadic pulses.

dialpulsemethod

signalingflags (bit 0)

mask

0x0

Determines the dialing type:
0 DTMF dialing
1 decadic dialing

errorearlyanswer

signalingflags (bit 1)

mask

0x0

If this parameter is set to 1, an answer signal before all digits have been dialed is an error, and the TCP clears the call.

NMScountry

NMScountry

count

31
(Australia)

NMS code for the target country.

Miscellaneous

mintimeconnected

mintimeconnected

ms

200

Inbound: the minimum time the TCP has to remain in the connected state (in order to allow the switch to bill the call).

incomingqualtime

incomingqualtime

ms

65

Inbound: signaling bits qualification time while playing ring tone.

releaseguardtime

releaseguardtime

ms

1000

Inbound: minimum time the release guard signal must be on.

timewaitunblock

timewaitunblock

ms

0

Time the TCP waits after receiving the command to unblock the line, before actually doing it and going to idle.

timeinterdigit

timeinterdigit

ms

400

Inbound: minimum time between trains of decadic pulses.

maxbillingpulse

maxbillingpulse

ms

200

Outbound: maximum duration of billing pulse (for those protocols in which the line code of a billing pulse is the same as clear back).

maxdecadicpulse

maxdecadicpulse

ms

100

Inbound: maximum duration of decadic pulse (for those protocols in which the line code of a decadic pulse is the same as clear forward).
The following parameters are reserved for NMS internal use: alarmsonqualtime alarmsoffqualtime

*Caution:*	Most of the parameters that follow are signaling-specific: changing their value will invalidate any approval certificate for the used board, and may cause the board to malfunction. These parameters are described here for reference purposes only.

NCC Field Name	ADI Field Name	Type/Unit	Default	Description
seizureacktime	seizureacktime	ms	10000	Outbound: Specifies time to wait for seizure acknowledgment after seizing the line.
seizurewaittime	seizurewaittime	ms	200	Outbound: Specifies the time to wait to be seized in a two-way trunk, after the TCP seized the line.
answerwaittime	answerwaittime	count	90	Outbound: Specifies the maximum time for the protocol to wait after the call accepted indication until the phone is answered (seconds).
acceptwaittime	acceptwaittime	ms	20000	Outbound: Specifies the maximum time for the protocol to wait after dialing before being notified that either the call has been accepted and the phone is ringing, or that the call has been rejected.
digitspilltime	digitspilltime	ms	20000	Inbound: Specifies the total time the dialing process is allowed to take.
bitqualtime	bitqualtime	ms	20	Specifies the qualification time for bit changes.
interdigitreceivetime	interdigitreceivetime	ms	5000	Inbound: While receiving decadic pulses, if the number of expected incoming digits is not known, this parameter specifies the time between two trains of pulses to conclude that the incoming dial string is finished.
winktime	winktime	ms	150	Inbound: Specifies the duration of an inbound wink. Depending on the target country, the wink has a different meaning and occurs at different phases of call setup.
toneontime	toneontime	ms	80	Specifies the time a DTMF tone should be ON while dialing.
toneofftime	toneofftime	ms	80	Specifies the time a DTMF tone should be OFF while dialing.
pulseontime	pulseontime	ms	50	Specifies the time a pulse should be ON while dialing with decadic pulses.
pulseofftime	pulseofftime	ms	50	Specifies the time a pulse should be OFF while dialing with decadic pulses.
hightoneamplitude	hightoneamplitude	IDU	352	Specifies the amplitude of the higher frequency of the DTMF tones while dialing.
lowtoneamplitude	lowtoneamplitude	IDU	440	Specifies the amplitude of the lower frequency of the DTMF tones while dialing.
interdigitsendtime	interdigitsendtime	ms	700	Outbound: Specifies the time between two trains of pulses while dialing with decadic pulses.
dialpulsemethod	signalingflags (bit 0)	mask	0x0	Determines the dialing type: `0` `DTMF dialing` `1` `decadic dialing`
errorearlyanswer	signalingflags (bit 1)	mask	0x0	If this parameter is set to 1, an answer signal before all digits have been dialed is an error, and the TCP clears the call.
NMScountry	NMScountry	count	31 (Australia)	NMS code for the target country.
Miscellaneous
mintimeconnected	mintimeconnected	ms	200	Inbound: the minimum time the TCP has to remain in the connected state (in order to allow the switch to bill the call).
incomingqualtime	incomingqualtime	ms	65	Inbound: signaling bits qualification time while playing ring tone.
releaseguardtime	releaseguardtime	ms	1000	Inbound: minimum time the release guard signal must be on.
timewaitunblock	timewaitunblock	ms	0	Time the TCP waits after receiving the command to unblock the line, before actually doing it and going to idle.
timeinterdigit	timeinterdigit	ms	400	Inbound: minimum time between trains of decadic pulses.
maxbillingpulse	maxbillingpulse	ms	200	Outbound: maximum duration of billing pulse (for those protocols in which the line code of a billing pulse is the same as clear back).
maxdecadicpulse	maxdecadicpulse	ms	100	Inbound: maximum duration of decadic pulse (for those protocols in which the line code of a decadic pulse is the same as clear forward).

6.5 Special TCP Behavior

The following sections describe operations that are specific to the AP2 TCP within the framework of Natural Call Control.

6.5.1 Inbound Calls: Retrieving Digits All at Once

With the AP2 TCP, after NCCEVN_INCOMING_CALL is received, the calledaddr field in the NCC_CALL_STATUS structure contains all received digits. The callingaddr, usercategory and tollcategory fields are NULL.
The parameter NCC.X.ADI_AP2.digitnumber determines the number of digits the TCP should expect from the calling party. The default is 7.

6.5.2 Inbound Calls: Receiving Digits One at a Time

To receive digits one at a time make sure the Ncc.Start.OverlappedReceiving parameter is set.
The AP2 TCP does not recognize ANI or category digits. Digits are presented in the order in which they arrive. The NCC.X.ADI_AP2.digitnumber parameter determines how many digits to expect.

6.5.3 Billing Pulses

If the network provides this service, an outbound call receives billing pulses during the Connected state. These are brief variations in the state of the signaling bits, that signal that a unit of cost has been billed to the call. The actual price of a unit of cost changes from network to network, as does the frequency with which billing pulses are received.
An application placing outbound calls can set the bit NCC_REPORT_BILLING in the NCC.START.eventmask parameter to enable the reception of billing pulse events. These are presented as NCCEVN_BILLING_INDICATION events by Natural Access. The application can then count the events to calculate the cost of the call.

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