Section 8.12.2.5. ONS Groups with SIP Subscriber as Master/Slave

8.12.2.5. ONS Groups with SIP Subscriber as Master/Slave

Requirements

The ONS group must not contain any Anate, TDM or HFA subscriber, if the master is a SIP subscriber. The slaves must also be SIP subscribers.

If the SIP subscriber is a slave in the ONS group then the master can be a TDM or HFA subscriber (SIP slave is added via AUXDIGI and SIP number in REMAC of ONS Group).

The following combinations are possible for HFA, TDM and SIP subscribers:

Table 54. Combinations of an ONS group with HFA, TDM and SIP subscribers

	Slave: SIP	Slave: HFA	Slave TDM
Master: SIP	x	---	---
Master: HFA	x	x	x
Master: TDM	x	x	x

The ONS group must not contain an external mobile phone.
Parallel ringing must be initiated by the SIP subscriber (=MASTER).

Service Information

ONS group features are limited. Only the currently supported SIP phone features are supported.
Activation of local features on the SIP phone is not signaled to the system and therefore these features cannot be controlled by the system.
Some system features are not released for SIP phones and some features exist only for SIP phones. Therefore there are cases when ONS SIP groups behave differently than ONS classic groups.
COS MULTRA (multiple transactions - the station can be seized multiple times) is a parameter which might be set for SIP devices, because it is needed for some features to work correctly. When MULTRA is set, the busy state of the SIP device is ignored by the system and a SIP phone is seized.
Members display
ONS SIP members keep their own idle display, showing their number rather than the master's number.

The parameter DISPRSTN AMO PERSI:COPIN does not apply for SIP ONS groups. The master number will be always shown for internal SIP ONS calls.
ACL
- Call forwarding:
  ACL reports call forwarding situations differently depending of call forward activation (local or system), the COS MULTRA parameter and which SIP ONS member is called.
  
  Remark: Call Forward Unconditional/Busy activated locally on a slave SIP phone is executed and reported as CF No Answer in ACL messages.
- Incoming Calls:
  ACL reports incoming calls differently to ONS scenarios depending on the COS MULTRA and Local Call Waiting settings.

Local feature interaction

Local Do not Disturb (only for SIP subscribers)
If a member has DND (Do not Disturb) activated locally, all the other ONS members are alerted shortly and then cleared when the member with DND disconnects.

When DND is set for the ONS member, the behavior differs depending on whether the member is a master or slave. If the member is a master, the calling party gets the disconnect message in dialing state. If the member is a slave, the calling party gets the disconnect message in ringback state, because the master acknowledged the call just beforehand. In this second case, the DND set for the slave is processed for the calling party as a call reject.

Remark: DND for SIP cannot be set using AMO ACTDA.

Local Call Forward
A SIP phone can activate internal Call Forward (SIP-specific feature). The system is not informed of this action. Therefore call forward will be only executed when the SIP phone is reached.

When a member has activated a local Call Forward, a call to the SIP ONS group will ring for all members and then it will be forwarded to the call forward destination.

Remarks:

If both Call Forwards No Reply are set (local on the phone and with AMO ACTDA) the one with the shorter no answer timer will be executed.

If master and slave have the same type of local Call Forward activated, the master call forward will be executed.
Deflect call
Deflect is a local feature that can be used by a SIP phone to transfer the call in a ringing state. When one ONS SIP member invokes this feature, the call will be transferred to the new destination.
Refuse call
Refuse is a local feature that can be used by a SIP phone to reject a call. When one ONS SIP member invokes this feature, the call will be disconnected.
Local Do not Disturb
If a member has DND (Do not Disturb) activated locally, all the other ONS members are alerted shortly and then cleared when the member with DND disconnects.

When DND is set for the ONS member, the behavior differs depending on whether the member is a master or slave. If the member is a master, the calling party gets the disconnect message in dialing state. If the member is a slave, the calling party gets the disconnect message in ringback state, because the master acknowledged the call just beforehand. In this second case, the DND set for the slave is processed for the calling party as a call reject.

Remark: DND for SIP cannot be set using AMO ACTDA.
Local Call Log
Any call to the SIP ONS group will be saved in the alerted member's call log.

Second call

Call Waiting is a local SIP phone feature that can only be used if COS MULTRA is set. The list below contains an overview of ONS group behavior. Call Waiting for SIP phones is possible when the SIP phone is in talk state. Call Waiting for SIP phones is not possible when the SIP phone is in ringing state.

	ONS group state	action	result when busy SIP has CW on	result when busy SIP has CW off
COS MULTRA set	ONS is busy in ring state	call master	call cleared, busy	call cleared, busy
	ONS is busy in ring state	call slave	call cleared, busy	call cleared, busy
	ONS is busy, master is in talk state	call master	ONS members ring	ONS members ring shortly and then call cleared, busy
	ONS is busy, master is in talk state	call slave	ONS members ring	ONS members ring shortly and then call cleared, busy
	ONS is busy, slave is in talk state	call master	ONS members ring	ONS members ring shortly and then call cleared, busy
	ONS is busy, slave is in talk state	call slave	ONS members ring	ONS members ring shortly and then call cleared, busy
COS MULTRA not set	ONS is busy in ring state	call master	call cleared, busy	call cleared, busy
	ONS is busy in ring state	call slave	call cleared, busy	call cleared, busy
	ONS is busy, master is in talk state	call master	call cleared, busy	call cleared, busy
	ONS is busy, master is in talk state	call slave	call cleared, busy	call cleared, busy
	ONS is busy, slave is in talk state	call master	call cleared, busy	call cleared, busy
	ONS is busy, slave is in talk state	call slave	call cleared, busy	call cleared, busy

Remark: For the situation when COS MULTRA is set and busy SIP phone has Call Waiting off:

ONS is busy, master is in talk state: the call is disconnected before the request is accepted.
ONS is busy, slave is in talk state: the call is disconnected after request is accepted.

Out of Service
If the master SIP device is out of service any incoming call to the ONS group is blocked.

If one of the slave SIP devices is out of service the other members work as usual.

Remark: If the SIP phone is unplugged, it is not signaled as "Out of Service" to the system.

Restriction

Handover will not be supported
PIN is not supported for SIP devices; therefore the "PIN permanent" feature isn't used.

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