Polycom SIP 3.1 manual Refer to Call Handling Configuration call, Sharing that registration

			Configuration Files
	Permitted
Attribute	Values	Default	Interpretation
reg.x.lineKeys	1 to max	1	max = the number of line keys on the phone.
			max = 1 on SoundStation IP 4000, 6000,
			7000,
			max = 2 on IP 301, 320, 330, 430,
			max = 3 on IP 501,
			max = 4 on IP 550, 560,
			max = 6 on IP 600,
			max = 48 on IP 601, 650, 670 (without any
			Expansion Modules attached, only 6 line keys
			are available)
			The number of line keys on the phone to be
			associated with registration ‘x’.
reg.x.callsPerLineKey	1 to 34 OR	24 OR	For the SoundPoint IP 650 and 670, the
	1 to 24 OR	8	permitted range is 1 to 34 and the default is
			34.
	1 to 8
			For the SoundPoint IP 550, 560, 600, and
			601, the permitted range is 1 to 24 and the
			default is 24.
			For all other phones the permitted range is 1
			to 8 and the default is 8.
			This is the number of calls or conferences
			which may be active or on hold per line key
			associated with this registration.
			Note that this overrides
			call.callsPerLineKey for this registration.
			Refer to Call Handling Configuration <call/>
			on page A-64.
			Note: A call active on another phone on a
			shared line counts as a call for every phone
			sharing that registration.
reg.x.bargeInEnabled	0, 1	Null	Allow remote user of SCA to interrupt call.
			(Works in a similar way to resume.)
			If set to 1, barge-in is enabled for line x.
			If set to 0 or Null, barge-in is disabled for line
			x.
reg.x.outboundProxy.address	dotted-decimal IP	Null	IP address or host name and port of a SIP
	address or host		server to which the phone shall send all
	name		requests.
reg.x.outboundProxy.port	1 to 65535	5060

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