17.1 Introduction

17.2 Capability Mask

17.3 Signaling Overview

17.4 Parameters

17.4.1 Editable Parameters

17.4.2 Non-editable Parameters

17.5 Special TCP Behavior

17.5.1 Inbound Calls: Retrieving Digits All at Once

17.5.2 Inbound Calls: Receiving Digits One at a Time

17.1 Introduction

This chapter describes the Wink Start (WNK) signaling protocol and TCP parameters. It provides the following information:

• Overview of the WNK protocol signaling.

• WNK parameters.

• Operations that are specific to the WNK protocol within the framework of Natural Call Control.

This protocol family includes protocols used on T1 in the USA, Hong Kong and Taiwan. The protocol uses one-bit signaling (or presence or absence of current in the analog case), and owes its name to the wink (brief presence of current or variation of the signaling bit) that the inbound side uses to acknowledge line seizure. Register signaling is performed by in-band DTMF or MF tones, or by out-of-band decadic pulses.

The International Wink Start (IWK), DID, and OGT protocols have been incorporated into the Wink Start protocol. See Section 17.4 for more information about parameters used to support these older protocols.

17.2 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.

17.3 Signaling Overview

The wink start protocol is symmetrical (same implementation from the network or from customer premises equipment).

The signaling channels supporting the WNK line signaling protocol are referred to as A_f and 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).

In the U.S. and Taiwan, the idle code is AB=00

In Hong Kong, two variations are possible in the Hong Kong Telecom network:

• Pulse on busy (idle code is AB=00)

• Pulse on idle (idle code is AB=11)

The two variations execute call setup in exactly the same way, except that all bit changes are opposite. The WNK TCP parameter optionflags, bit 1, specifies which variation to use.

The line signaling for a typical call is illustrated in the following table. The table represents the "pulse on busy" variation:

State	Outbound AfBf	Direction	Inbound Ab
Idle	00		00
Seizure	11		00
Seizure Acknowledge	11		00-11-00 (wink)
The outbound side starts to send the address information using DTMF tones, MF tones, or decadic pulses. If the method is decadic pulses, the Af bit is switched off (pulse on) and on (pulse off) repeatedly to signal the digits.
Register signaling: digit spill	DTMF or MF		00
Register signaling: pulse dial	00 pulse on		00
	11 pulse off		00
All the address information has been transferred. The inbound side must accept or reject the call. It does so by playing the ring or the busy tone on the voice path. If the call is rejected, the outbound side is supposed to switch back to signaling AB = 00 (idle), thus clearing the line.
Clear forward and idle	00		00
If the call is accepted, the inbound side answers the call by flipping both backward bits to 1.
Answer - conversation state	11		11
Depending on which side hangs up the call first, a clear back signal or a clear forward signal is generated. Idle follows.
Inbound hangs up first: Clear back	11		00
Outbound hangs up first: Clear forward	00		00 or 11
Idle	00		00

In analog variations the digital bit signaling is translated into E & M or DID analog signaling by the line interface circuitry on the board.

In U.S. implementations, the wink start protocol can transfer ANI (caller ID) information in addition to DID digits (direct inward dialing - the called address). A separator tone is used to distinguish between DID and ANI digits in the DTMF digit spill. Usually the separator tone is a * (941+1209 Hz). The parameter NCC.X.ADI_WNK.anididtone (see following table) determines the TCP's behavior with respect to ANI digits.

Taiwan and Hong Kong do not use ANI digits.

17.4 Parameters

The WNK TCP is programmed for operation within different countries and networks by a number of TCP-specific parameters. These parameters are stored within the parameter category NCC.X.ADI_WNK.

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.
  Note: If in the previous releases of NMS CAS you used the International Wink Start protocol (IWK), it has now been incorporated into the Wink Start protocol. If you were using the DID protocol, the Wink Start protocol should now be used by setting the parameter trunkdirection to TRUNK_INBOUND. If you were using the OGT protocol, the Wink Start protocol should now be used by setting the parameter trunkdirection to TRUNK_OUTBOUND.

17.4.1 Editable Parameters

The following table describes NCC.X.ADI_WNK parameters (within the parameter category NCC.X.ADI_WNK) that you may modify. Also listed are the equivalent ADI.WNK parameters, to assist with migration from ADI to NCC.

NCC Field Name	ADI Field Name	Type/Unit	Default	Description
numdigits	numdigits	count	7	Relevant to inbound protocol. Specifies the number of incoming digits to expect.
variabledigits	optionflags (bit 0)	mask	0x0	Determines what to do if a timeout occurs during digit reception: 0 Reject the call. 1 Notify the host of an inbound call.
idlebits	optionflags (bit 1)	mask	0x0	(Hong Kong only): 0 Use pulse on busy line signaling. 1 Use pulse on idle line signaling.
trunkdirection	optionflags (bits 2 and 3)	mask	0x0	Trunk direction: 0 Bidirectional (default) 1 Inbound 2 Outbound
playcleardown	optionflags (bit 4)	mask	0x0	If 1, play cleardown tone while hanging up (inbound).
defaultrejecttone	optionflags (bits 5,6,7)	count	2	Tone to play if NCC.START.waitforPCtime expires: 0 Fast busy (reorder) 1 Ring 2 Busy
BCD_BitFlag	optionflags (bit 8)	integer	0	Controls behavior of the B, C, and D bits: 0 BCD bits follow the A bit (default). 1 BCD bits are set to 101.
transfersupport	optionflags (bit 12)	mask	0x0	Flag to select whether PBX transfer is allowed: 0 Transfer commands are disabled. 1 Transfer commands are allowed.

17.4.2 Non-editable Parameters

The following NCC.X.ADI_WNK parameters are country- or network-specific, and cannot be modified. Also listed are the equivalent ADI.WNK 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
Bit changes qualification timers - during different phases of the protocol.
qualtime	qualtime	ms	30	Qualification time for signaling bit going to ON, during register signaling phase of call setup.
Signaling defaults
compelledKP	signalingflags (bit 0)	mask	0x0	Register signaling - if 1, prefix with/expect compelled KP tone. Used in Taiwan.
immediatestart	signalingflags (bit 1)	mask	0x0	Line signaling - if 1, inbound doesn't send a wink (immediate start).
signalingmethod	signalingflags (bis 2 and 30)	count	0	Determines tones register signaling is performed with: 0 DTMF 1 MF 2 Decadic signaling
receiveKPST	signalingflags (bit 4)	mask	0x0	If set, when register signaling is performed with MFs, inbound looks for the KP and ST tones.
noSTreceptionOK	signalingflags (bit 5)	mask	0x0	If noSTreceptionOK is set, determines whether the TCP will accept signaling if the ST tone does not arrive.
sendKPST	(no antecendent)	mask	0x0	(Outbound only) determines whether or not to send KP and ST tones when dialing with MF tones: 0 Send KP and ST tones. 1 Do not send KP and ST tones.
anibeforedid	signalingflags (bit 6)	ms	0x0	If set, ANI digits come before the DID digits.
anididtone	separatordigits (low byte)	mask	0x0	Tone that specifies a separator between DID and ANI digits. Set to 0x2a for *. Set to 0 for no separator.
endofdigitstone	separatordigits (high byte)	mask	0x46	Tone that specifies the end of digits. F is the default.
winktime	winktime	ms	200	Inbound: Specifies the duration of the wink used by the TCP to signal seizure acknowledgment.
prewinktime	prewinktime	ms	100	Inbound: Time to wait before sending the wink that acknowledges the seizure.
More timers for the inbound protocol.
wait1stdigittime	digitswaittime (low byte)	100 ms	70	Inbound: Time (in 100 ms units) to wait after seizure acknowledge for the first digit to arrive.
waitfordigitstime	digitswaittime (high byte)	100 ms	80	Inbound: Time (in 100 ms units) to wait after each digit arrives for the next digit.
Outbound protocol parameters
winkwaittime	winkwaittime	ms	10000	Outbound: Time to wait for seizure acknowledgement after seizing the line. Maximum time to wait for the far end to wink. Set to 0 if no wink is expected (immediate start).
minwinktime	minwinktime	ms	100	Outbound: Minimum duration of seizure acknowledgment wink.
maxwinktime	maxwinktime	ms	4900	Outbound: Maximum duration of seizure acknowledgment wink.
predialtime	predialtime	ms	70	Outbound: Time to wait after the wink to start dialing.
mfkpsttimeon	mfkpsttime	ms	80	Outbound: Duration of the KP and ST tones, if transmitted.
mfkpsttimeoff	mfkpstontime	ms	80	Outbound: Duration of the silence after the KP and ST tones.
mfkpstampl	mfkpstampl	IDU	352	Outbound: Amplitude of the KP and ST tones.
releaseguardtime	releaseguardtime	ms	1000	Outbound: Time after an outbound call in which the TCP will not place another call.
assumenewdigittime	assumenewdigittime	ms	0	Inbound: There are some switches that leave too short a time between MF tones to detect the silence. This parameter adjusts the minimum amount of silence that must occur between consecutive MF tones before the TCP assumes they represent different digits. Set to slightly more than the full duration of a MF digit cycle (tone on + off).
connectbacktime	connectbacktime	ms	100	Time to wait after sending transfer back hookflash is the PBX was playing busy.
xferstring	xferstring	string[6]	"!;"	Prefix dial string for call transfer. The string is dialed before dialing the number, where: ! Flash hook. ; (semicolon) Wait for precise dial tone.
connstring	connstring	string[6]	"!"	String for transfer back to the Connected state with the first call. It is dialed if a call transfer fails, where: ! Flash hook.

The following parameters are reserved for NMS internal use:

• alarmsonqualtime

• alarmsoffqualtime

17.5 Special TCP Behavior

The following sections describe operations specific to Wink Start-derived TCPs within the framework of Natural Call Control.

17.5.1 Inbound Calls: Retrieving Digits All at Once

With Wink Start-derived TCPs, after NCCEVN_INCOMING_CALL is received, the calledaddr field in the NCC_CALL_STATUS structure usually contains all received digits. The callingaddr, usercategory and tollcategory fields are usually NULL.

Note that with the WNK0 TCP, digital two-way Wink Start, if the parameter NCC.X.ADI_WNK.anididtone is set correctly, any ANI digits in the digit string are presented to the application in the callingaddr field.

The parameter NCC.X.WNK.numdigits determines the number of digits the TCP should expect from the calling party (including ANI digits and the * symbol, when expecting ANI). The default is 3.

17.5.2 Inbound Calls: Receiving Digits One at a Time

To receive digits one at a time, make sure the Ncc.Start.OverlappedReceiving parameter is set.

In general, digits are presented in the order in which they arrive. If ANI are present, the DTMF tones * and # are also present in the digits received by the TCP. Only the * (separator between ANI and DID) is passed to the application though, not the #, that signals the end of the digit string (ST tone). When receiving digits one at a time, the application must know the order of the fields in the digit string (ANI or DID first).