Обнаружил закономерность - если подключены пять линий, то звонит один ext, все как надо.
15:49:04 [105804] 0: RingTime(29) First Stop
15:49:06 [105823] 0: RingTime(238) Second Ring
15:49:08 [105844] 0: CallerId=
15:49:08 [105844] 0: ==17:WaitAnswerDeviceOk
15:49:08 [105844] 0: HotLineEnabled with [1301611]
15:49:08 [105844] 0: End Input Default Route [0]
15:49:08 [105844] 0: Call Proxy with [1301611]
15:49:08 [105844] 0: ==7:Inviting
15:49:08 [105844] 0: VoIP CallOut, Invite <sip:1301611@192.168.0.241:5060;user=phone>
15:49:08 [105845] 0: 701=DIALING
15:49:08 [105848] 0: 701=PROCEEDING
15:49:08 [105848] 0: 701=RINGBACK
15:49:08 [105849] 0: ==8:RingBack
15:49:08 [105850] 0: 701=RINGBACK
15:49:16 [105931] 0: 701=CONNECTED
15:49:16 [105931] 0: Peer=192.168.0.241:12018, PT=0, RecvOnly=0
15:49:16 [105931] 0: FxoHookOff
15:49:16 [105931] 0: SetInputGain(-2)
15:49:16 [105931] 0: RtpApiTalk[0,0], Peer=192.168.0.241:12018, PT=0, FC=6, NewOOB=0
15:49:16 [105931] 0: ==14:Talking
15:49:17 [105931] 0: SetTalkMode[1,1]
15:49:22 [105988] 0: 701=DISCONNECT
15:49:22 [105988] 0: Release Active Dlg
15:49:22 [105988] 0: ==15:PlayBusyTone
15:49:25 [106017] 0: Fxo Detected CPT Busy(1)
15:49:25 [106018] DSP_ch0_check=0
15:49:25 [106018] 0: FxoHookOn
15:49:25 [106018] 0: ==3:Idle
15:49:25 [106018] 0: SetInputGain(4)
15:49:25 [106018] 0: SetFax(1)=0
Но стоит разомкнуть любую из пяти линий, например 3. Получаю.
15:52:05 [107613] 3: ===== New FxoLineStatus 0
15:52:22 [107788] 0: Fxo Ringing
15:52:22 [107790] 0: RingTime(34) First Stop
15:52:24 [107803] 0: RingTime(182) Second Ring
15:52:25 [107814] 0: CallerId=
15:52:25 [107814] 0: ==17:WaitAnswerDeviceOk
15:52:25 [107814] 0: HotLineEnabled with [1301611]
15:52:25 [107814] 0: End Input Default Route [0]
15:52:25 [107814] 0: Call Proxy with [1301611]
15:52:25 [107814] 0: ==7:Inviting
15:52:25 [107814] 0: VoIP CallOut, Invite <sip:1301611@192.168.0.241:5060;user=phone>
15:52:25 [107815] 0: 701=DIALING
15:52:25 [107818] 0: 701=PROCEEDING
15:52:25 [107818] 0: 701=RINGBACK
15:52:25 [107819] 0: ==8:RingBack
15:52:25 [107819] 0: 701=RINGBACK
15:52:28 [107843] 2: Fxo Ringing
15:52:28 [107844] 2: RingTime(53) First Stop
15:52:35 [107913] 2: RingTime Stopped
15:52:35 [107913] 2: ==3:Idle
15:52:35 [107913] 2: SetInputGain(4)
15:52:35 [107913] 2: SetFax(1)=0
15:52:40 [107963] 2: Fxo Ringing
15:52:40 [107964] 2: RingTime(43) First Stop
15:52:43 [107993] 2: RingTime(342) Second Ring
15:52:44 [108004] 2: FxoHookOff
15:52:44 [108004] 2: SetInputGain(-2)
15:52:44 [108004] 2: SetFxoHookOff()=0, CallerId=
15:52:44 [108004] 2: ==17:WaitAnswerDeviceOk
15:52:44 [108004] 2: ==4:GetDtmf
15:52:53 [108092] 0: 701=CONNECTED
15:52:53 [108092] 0: Peer=192.168.0.241:12590, PT=0, RecvOnly=0
15:52:53 [108092] 0: FxoHookOff
15:52:53 [108092] 0: SetInputGain(-2)
15:52:53 [108092] 0: RtpApiTalk[0,0], Peer=192.168.0.241:12590, PT=0, FC=6, NewOOB=0
15:52:53 [108092] 0: ==14:Talking
15:52:53 [108093] 0: SetTalkMode[1,1]
15:52:54 [108105] 2: DTMF Timeout #1
15:52:54 [108105] 2: ==15:PlayBusyTone
15:52:57 [108133] 0: Fxo Detected CPT Busy(1)
15:52:57 [108133] 0: Bye at Talking
15:52:57 [108133] 0: ==15:PlayBusyTone
15:52:57 [108134] DSP_ch0_check=0
15:52:57 [108134] 0: FxoHookOn
15:52:57 [108134] 0: ==3:Idle
15:52:57 [108134] 0: SetInputGain(4)
15:52:57 [108134] 0: SetFax(1)=0
15:52:57 [108134] 0: 701=DISCONNECT
15:52:57 [108134] 0: Release Old Dlg #2
15:52:57 [108135] 2: Start Btc Learning
15:52:59 [108158] 2: Fxo Detected CPT Busy(1)
15:52:59 [108158] DSP_ch2_check=0
15:52:59 [108158] 2: FxoHookOn
15:52:59 [108158] 2: ==3:Idle
15:52:59 [108158] 2: SetInputGain(4)
15:52:59 [108158] 2: SetFax(1)=0
Или вторую
15:54:13 [108899] 1: ===== New FxoLineStatus 0
15:54:25 [109021] 0: Fxo Ringing
15:54:25 [109022] 0: RingTime(28) First Stop
15:54:27 [109033] 0: RingTime(158) Second Ring
15:54:28 [109043] 3: Fxo Ringing
15:54:28 [109045] 3: RingTime(47) First Stop
15:54:29 [109054] 0: CallerId=
15:54:29 [109054] 0: ==17:WaitAnswerDeviceOk
15:54:29 [109054] 0: HotLineEnabled with [1301611]
15:54:29 [109054] 0: End Input Default Route [0]
15:54:29 [109054] 0: Call Proxy with [1301611]
15:54:29 [109054] 0: ==7:Inviting
15:54:29 [109054] 0: VoIP CallOut, Invite <sip:1301611@192.168.0.241:5060;user=phone>
15:54:29 [109055] 0: 701=DIALING
15:54:29 [109058] 0: 701=PROCEEDING
15:54:29 [109058] 0: 701=RINGBACK
15:54:29 [109059] 0: ==8:RingBack
15:54:29 [109059] 0: 701=RINGBACK
15:54:30 [109066] 3: RingTime(281) Second Ring
15:54:31 [109073] 3: FxoHookOff
15:54:31 [109073] 3: SetInputGain(-2)
15:54:31 [109073] 3: SetFxoHookOff()=0, CallerId=
15:54:31 [109073] 3: ==17:WaitAnswerDeviceOk
15:54:31 [109074] 3: ==4:GetDtmf
15:54:41 [109175] 3: DTMF Timeout #1
15:54:41 [109175] 3: ==15:PlayBusyTone
15:54:42 [109189] 0: 701=CONNECTED
15:54:42 [109189] 0: Peer=192.168.0.241:12256, PT=0, RecvOnly=0
15:54:42 [109189] 0: FxoHookOff
15:54:42 [109189] 0: SetInputGain(-2)
15:54:42 [109189] 0: RtpApiTalk[0,0], Peer=192.168.0.241:12256, PT=0, FC=6, NewOOB=0
15:54:42 [109189] 0: ==14:Talking
15:54:43 [109193] 0: SetTalkMode[1,1]
15:54:44 [109206] 3: Start Btc Learning
15:54:47 [109233] 0: Fxo Detected CPT Busy(1)
15:54:47 [109233] 0: Bye at Talking
15:54:47 [109233] 0: ==15:PlayBusyTone
15:54:47 [109233] 3: Fxo Detected CPT Busy(1)
15:54:47 [109233] DSP_ch3_check=0
15:54:47 [109233] 3: FxoHookOn
15:54:47 [109233] 3: ==3:Idle
15:54:47 [109233] 3: SetInputGain(4)
15:54:47 [109233] 3: SetFax(1)=0
15:54:47 [109234] DSP_ch0_check=0
15:54:47 [109234] 0: FxoHookOn
15:54:47 [109234] 0: ==3:Idle
15:54:47 [109234] 0: SetInputGain(4)
15:54:47 [109234] 0: SetFax(1)=0
15:54:47 [109234] 0: 701=DISCONNECT
15:54:47 [109234] 0: Release Old Dlg #2
При отключении первой линии и звонке на вторую
15:56:45 [110419] 1: ===== New FxoLineStatus 1
15:56:49 [110458] 2: ===== New FxoLineStatus 0
15:57:08 [110647] 3: Fxo Ringing
15:57:08 [110648] 3: RingTime(25) First Stop
15:57:09 [110653] 3: RingTime(94) Second Ring
15:57:10 [110664] 3: FxoHookOff
15:57:10 [110664] 3: SetInputGain(-2)
15:57:10 [110664] 3: SetFxoHookOff()=0, CallerId=
15:57:10 [110664] 3: ==17:WaitAnswerDeviceOk
15:57:10 [110664] 3: ==4:GetDtmf
15:57:15 [110718] 3: Fxo Detected CPT Busy(1)
15:57:15 [110718] 3: ==15:PlayBusyTone
15:57:15 [110718] DSP_ch3_check=0
15:57:15 [110718] 3: FxoHookOn
15:57:15 [110718] 3: ==3:Idle
15:57:15 [110718] 3: SetInputGain(4)
15:57:15 [110718] 3: SetFax(1)=0
15:57:19 [110755] 1: Fxo Ringing
15:57:19 [110756] 1: RingTime(30) First Stop
15:57:21 [110773] 1: RingTime(215) Second Ring
15:57:22 [110783] 3: Fxo Ringing
15:57:22 [110784] 3: RingTime(43) First Stop
15:57:23 [110794] 1: CallerId=
15:57:23 [110794] 1: ==17:WaitAnswerDeviceOk
15:57:23 [110794] 1: HotLineEnabled with [2301612]
15:57:23 [110794] 1: End Input Default Route [0]
15:57:23 [110794] 1: Call Proxy with [2301612]
15:57:23 [110794] 1: ==7:Inviting
15:57:23 [110795] 1: VoIP CallOut, Invite <sip:2301612@192.168.0.241:5060;user=phone>
15:57:23 [110795] 1: 702=DIALING
15:57:23 [110798] 1: 702=PROCEEDING
15:57:23 [110799] 1: 702=RINGBACK
15:57:23 [110799] 1: ==8:RingBack
15:57:23 [110799] 1: 702=RINGBACK
15:57:29 [110853] 3: RingTime Stopped
15:57:29 [110853] 3: ==3:Idle
15:57:29 [110853] 3: SetInputGain(4)
15:57:29 [110853] 3: SetFax(1)=0
15:57:33 [110893] 1: RingTime Stopped
15:57:33 [110893] 1: Cancel at Ringback
15:57:33 [110893] 1: 702=CANCEL
15:57:33 [110893] 1: ==15:PlayBusyTone
15:57:33 [110894] DSP_ch1_check=0
15:57:33 [110894] 1: FxoHookOn
15:57:33 [110894] 1: ==3:Idle
15:57:33 [110894] 1: SetInputGain(4)
15:57:33 [110894] 1: SetFax(1)=0
15:57:33 [110894] 1: 702=DISCONNECT
15:57:33 [110894] 1: Release Old Dlg #2
15:58:15 [111318] 2: ===== New FxoLineStatus 1
15:58:19 [111354] 0: ===== New FxoLineStatus 0
15:58:32 [111487] 1: Fxo Ringing
15:58:32 [111488] 1: RingTime(42) First Stop
15:58:33 [111493] 1: RingTime(109) Second Ring
15:58:34 [111503] 3: Fxo Ringing
15:58:34 [111504] 3: RingTime(60) First Stop
15:58:35 [111514] 1: CallerId=
15:58:35 [111514] 1: ==17:WaitAnswerDeviceOk
15:58:35 [111514] 1: HotLineEnabled with [2301612]
15:58:35 [111514] 1: End Input Default Route [0]
15:58:35 [111514] 1: Call Proxy with [2301612]
15:58:35 [111514] 1: ==7:Inviting
15:58:35 [111515] 1: VoIP CallOut, Invite <sip:2301612@192.168.0.241:5060;user=phone>
15:58:35 [111515] 1: 702=DIALING
15:58:35 [111518] 1: 702=PROCEEDING
15:58:35 [111519] 1: 702=RINGBACK
15:58:35 [111519] 1: ==8:RingBack
15:58:35 [111519] 1: 702=RINGBACK
15:58:37 [111533] 2: Fxo Ringing
15:58:37 [111534] 2: RingTime(30) First Stop
15:58:40 [111562] 3: RingTime(62) Second Ring
15:58:41 [111574] 3: FxoHookOff
15:58:41 [111574] 3: SetInputGain(-2)
15:58:41 [111574] 3: SetFxoHookOff()=0, CallerId=
15:58:41 [111574] 3: ==17:WaitAnswerDeviceOk
15:58:41 [111574] 3: ==4:GetDtmf
15:58:44 [111604] 2: RingTime Stopped
15:58:44 [111604] 2: ==3:Idle
15:58:44 [111604] 2: SetInputGain(4)
15:58:44 [111604] 2: SetFax(1)=0
15:58:47 [111635] 1: 702=CONNECTED
15:58:47 [111636] 1: Peer=192.168.0.241:13438, PT=0, RecvOnly=0
15:58:47 [111636] 1: FxoHookOff
15:58:47 [111636] 1: SetInputGain(-2)
15:58:47 [111636] 1: RtpApiTalk[0,0], Peer=192.168.0.241:13438, PT=0, FC=6, NewOOB=0
15:58:47 [111636] 1: ==14:Talking
15:58:47 [111636] 1: SetTalkMode[1,1]
15:58:50 [111665] 1: 702=DISCONNECT
15:58:50 [111665] 1: Release Active Dlg
15:58:50 [111665] 1: ==15:PlayBusyTone
15:58:51 [111675] 3: DTMF Timeout #1
15:58:51 [111675] 3: ==15:PlayBusyTone
15:58:53 [111696] DSP_ch1_check=0
15:58:53 [111696] 1: FxoHookOn
15:58:53 [111696] 1: ==3:Idle
15:58:53 [111696] 1: SetInputGain(4)
15:58:53 [111696] 1: SetFax(1)=0
15:58:54 [111706] 3: Start Btc Learning
15:58:56 [111728] 3: Fxo Detected CPT Busy(1)
15:58:56 [111728] DSP_ch3_check=0
15:58:56 [111728] 3: FxoHookOn
15:58:56 [111728] 3: ==3:Idle
15:58:56 [111728] 3: SetInputGain(4)
15:58:56 [111728] 3: SetFax(1)=0
настройки sip

1 и 2 линии зарегистрированы на Freepbx как trunk.