Troubleshooting EM_PARK Issues for E&M Digital CAS Signaling

Introduction

In digital E&M signaling on Cisco 2600, 3600, and MC3810 router platforms, some T1/E1 time slots can get stuck in the EM_PARK state. This is visible when you issue the show voice call summary command. This document explains how to troubleshoot this issue.

This output shows that some time slots are in the EM_PARK state. A time slot in the EM_PARK state is not used for voice calls.

Router#show voice call summary 
PORT      CODEC     VAD    VTSP STATE     VPM STATE
=====     ======    ===    ==========     ==========
1/0:0.1     -        -          -         EM_ONHOOK 
1/0:0.2     -        -          -         EM_PARK 
1/0:0.3     -        -          -         EM_PARK 
1/0:0.4     -        -          -         EM_ONHOOK 
1/0:0.5     -        -          -         EM_ONHOOK

Prerequisites

Requirements

There are no specific requirements for this document.

Components Used

The information in this document is based on these software and hardware versions:

• 
  

  Hardware—Cisco 2600, Cisco 3600, Cisco VG200, and MC3810 routers

  
  



• 
  

  Software—All

  
  

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.

Background Theory

In T1 CAS, for example, wink start signaling, when the PBX goes offhook, the router/gateway side time slot remains in the idle (EM_ONHOOK) state until the call is answered by a remote destination. The router time slot state changes to EM_OFFHOOK when the call is answered by the remote destination.

If the call does not connect, the router/gateway plays the inband reorder tones to the caller. Since the channel state on the router side is still EM_ONHOOK, the router is unable to hang up the channel. After the caller hangs up, the PBX needs to change its channel state from offhook to onhook.

In some cases, the PBXs do not send the onhook messages, with the help of the ABCD transitions. The router has a workaround for this called fake answer. Without the fake answer workaround, the channels hang in a state of EM_PARK indefinitely. See the Fake Answer section for more information.

Note: Calls can be stuck in the EM_PARK state on some T1 channels if the voice gateway router chasis is not electrically grounded properly. Refer to the hardware installation guide for more information about electrical grounding.

Conventions

Refer to Cisco Technical Tips Conventions for more information on document conventions.

Problem

There are two possible, major reasons that the time slot is stuck in the EM_PARK state:

• 
  

  The digital signal processor (DSP) is bad and has either hardware or software issues.

  
  



• 
  

  The PSTN switch/PBX sends a continuous offhook signal to the router and does not release it.

  
  

Solution

These are the solutions to this problem:

If the time slots in your system are stuck in the EM_PARK state, check the DSPs. Refer to Troubleshooting the DSP on NM-HDV for Cisco 2600/3600 Series Routers in order to check the DSPs.

If the DSPs are alive, the problem can be on the PSTN switch/PBX side or the Cisco IOS^® (router/gateway does not start the Fake Answer procedure). See the Fake Answer section for more information.

Fake Answer

The Cisco router/gateway waits for a default value of 30 seconds (use the timeouts wait-release and timeouts call-disconnect commands in order to change these values) after it knows that the time slot needs to be set from the PBX to onhook while it plays the reorder tone.

If this does not happen, the router moves the time slot to the EM_PARK state and starts another timer with a duration of 10 seconds. If the PBX still does not go onhook after the 10-second duration, the router tricks the PBX. The router sends a fake answer of a one second duration and then goes onhook.

After the router sends the fake answer signal, the router starts another timer of five minutes. If the PBX goes onhook, the timer stops and the router transitions the time slot to the EM_ONHOOK state. Otherwise, after five minutes it sends another fake answer signal of a one-second duration. The router repeats this process until the PBX goes onhook. The router forces the PBX to clear the call.

Note: This answering transition is not updated to any accounting record since the actual call is cleared. But, the PBX understands it as an answer and the user is probably charged for the one-second duration call.

If the DSP associated with the time slot in the EM_PARK state is alive and healthy and the problem persists, run the debug vpm all and debug vtsp all commands in order to see if Cisco IOS attempts to send the fake answer.

Note: You need to run the debugs for more than five minutes.

Note: In most cases, if the DSP is bad, the router does not perform the fake answer workaround. Refer to Troubleshooting the DSP on NM-HDV for Cisco 2600/3600 Series Routers for more information.

This debug output shows how a time slot becomes stuck in EM_PARK and how the fake answer workaround works.

Jan 11 17:19:00.767: htsp_dsp_message: SEND/RESP_SIG_STATUS: state=0xC timestamp
=44262 systime=31305235
Jan 11 17:19:00.767: htsp_process_event:
[4/1:1(10), EM_ONHOOK, E_DSP_SIG_1100]em_onhook_offhook htsp_setup_ind

!--- Offhook signal is received from the switch.

Jan 11 17:19:00.767: [4/1:1(10)] get_local_station_id calling num= calling name=
calling time=01/11 17:19 
Jan 11 17:19:00.767: vtsp_tsp_call_setup_ind (sdb=0x62BB7B14, tdm_info=0x0, tsp_
info=0x62BB4050, calling_number= calling_oct3 = 0x0, called_number= called_oct3 
= 0x81, oct3a=0x0): peer_tag=0
Jan 11 17:19:00.767: : ev.clg.clir is 0
ev.clg.clid_transparent is
0
ev.clg.null_orig_clg is 1
ev.clg.calling_translated is false

Jan 11 17:19:00.767: htsp_timer - 3000 msec
Jan 11 17:19:00.767: vtsp_do_call_setup_ind
Jan 11 17:19:00.767: vtsp_allocate_cdb,cdb 0x62DCEA70
Jan 11 17:19:00.767: vtsp_do_call_setup_ind: Call ID=112722, guid=62DC4230
Jan 11 17:19:00.767: vtsp_do_call_setup_ind: type=0, under_spec=1640890368, 
name=, id0=10, id1=1, id2=25038, calling=, called= subscriber=RegularLine
Jan 11 17:19:00.767: vtsp_do_normal_call_setup_ind
Jan 11 17:19:00.771: cc_api_call_setup_ind (vdbPtr=0x62BB7FA0, 
callInfo={called=
,called_oct3=0x81,calling=,calling_oct3=0x0,calling_oct3a=0x0,calling_xlated=fal
se,subscriber_type_str=RegularLine,fdest=0,peer_tag=0, prog_ind=3},callID=0x62DC
40DC)
Jan 11 17:19:00.771: cc_api_call_setup_ind type 1 , prot 0
Jan 11 17:19:00.771: vtsp_insert_cdb,cdb 0x62DCEA70
Jan 11 17:19:00.771: vtsp_open_voice_and_set_params 
Jan 11 17:19:00.771: dsp_close_voice_channel: [4/1:1:32995] packet_len=8 channel
_id=3 packet_id=75
Jan 11 17:19:00.771: dsp_open_voice_channel_20: [4/1:1:32995] 
packet_len=16 channel_id=3 packet_id=74 alaw_ulaw_select=0 
associated_signaling_channel=130 time_slot=2 serial_port=0
Jan 11 17:19:00.771: vtsp_modem_proto_from_cdb: cap_modem_proto 1073741824
Jan 11 17:19:00.771: vtsp_modem_proto_from_cdb: cap_modem_proto 1073741824
Jan 11 17:19:00.771: dsp_encap_config: [4/1:1:32995] packet_len=30 channel_id=3 
packet_id=92 
TransportProtocol 2 t_ssrc=0x0 r_ssrc=0x0 t_vpxcc=0x0 r_vpxcc=0x0
sid_support=1, tse_payload=65535, seq_num=0x0, redundancy=0
Jan 11 17:19:00.771: dsp_set_playout_delay
Jan 11 17:19:00.771: dsp_set_playout: [4/1:1:32995] packet_len=18 channel_id=3 p
acket_id=76 mode=1 initial=60 min=40 max=200 fax_nom=300 
dsp_set_playout_delay_config
Jan 11 17:19:00.771: dsp_set_playout_config
Jan 11 17:19:00.771: mode 0, init 60, min 40, max 200 playout default 
Jan 11 17:19:00.771: dsp_set_playout_config:mode 0, init 60, min 40, max 200 
Jan 11 17:19:00.771: dsp_set_playout_config: [4/1:1:32995] packet_len=18 channel
_id=3 packet_id=76 mode=1 initial=60 min=40 max=200 fax_nom=300 
Jan 11 17:19:00.771: dsp_echo_canceler_control: echo_cancel: 1
Jan 11 17:19:00.771: dsp_echo_canceler_control: [4/1:1:32995] echo_cancel 1, 
disable_hpf 0, flags=0x0, threshold=-21
Jan 11 17:19:00.771: dsp_echo_canceler_control: [4/1:1:32995] packet_len=12 
channel_id=3 packet_id=66 flags=0x0, threshold=-21
Jan 11 17:19:00.771: set_gains: FXx/E&M: msg->message.set_codec_gains.out_gain=0
Jan 11 17:19:00.771: dsp_set_gains: [4/1:1:32995] packet_len=12 channel_id=3 
packet_id=91 in_gain=0 out_gain=0
Jan 11 17:19:00.771: dsp_vad_enable: [4/1:1:32995] enable: packet_len=12 channel
_id=3 packet_id=78 thresh=-38
Jan 11 17:19:00.771: cc_process_call_setup_ind (event=0x62E63ACC)
Jan 11 17:19:00.771: >>>>CCAPI handed cid 32995 with tag 0 to app "DEFAULT"
Jan 11 17:19:00.771: sess_appl: ev(24=CC_EV_CALL_SETUP_IND), cid(32995), disp(0)
Jan 11 17:19:00.771: sess_appl: ev(SSA_EV_CALL_SETUP_IND), cid(32995), disp(0)
Jan 11 17:19:00.771: ssaCallSetupInd 
Jan 11 17:19:00.771: ccCallSetContext (callID=0x80E3, context=0x62DFBCF0)
Jan 11 17:19:00.771: ssaCallSetupInd cid(32995),
 st(SSA_CS_MAPPING),oldst(0), ev
(24)ev->e.evCallSetupInd.nCallInfo.finalDestFlag = 0
Jan 11 17:19:00.771: ccCallSetupAck (callID=0x80E3)
Jan 11 17:19:00.771: ccGenerateTone (callID=0x80E3 tone=8)
Jan 11 17:19:00.771: ccCallReportDigits (callID=0x80E3, enable=0x1)
Jan 11 17:19:00.771: vtsp_report_digit_control: enable=1: 
digit reporting enabled
Jan 11 17:19:00.771: cc_api_call_report_digits_done (vdbPtr=0x62BB7FA0, 
callID=0x80E3, disp=0)
Jan 11 17:19:00.771: : vtsp_get_digit_timeouts
Jan 11 17:19:00.771: sess_appl: ev(52=CC_EV_CALL_REPORT_DIGITS_DONE), 
cid(32995), disp(0)
Jan 11 17:19:00.771: cid(32995)st(SSA_CS_MAPPING)ev
(SSA_EV_CALL_REPORT_DIGITS_DONE)
oldst(SSA_CS_MAPPING)cfid(-1)csize(0)in(1)fDest(0)
Jan 11 17:19:00.771: ssaReportDigitsDone cid(32995) peer list: (empty)
Jan 11 17:19:00.771: ssaReportDigitsDone callid=32995 Enable succeeded
Jan 11 17:19:00.771: ccGenerateTone (callID=0x80E3 tone=8)
Jan 11 17:19:00.771: vtsp:[4/1:1:32995, S_SETUP_INDICATED, E_CC_SETUP_ACK]
Jan 11 17:19:00.775: act_setup_ind_ack 
Jan 11 17:19:00.775: vtsp_modem_proto_from_cdb: cap_modem_proto 0
Jan 11 17:19:00.775: vtsp_modem_proto_from_cdb: cap_modem_proto 0
Jan 11 17:19:00.775: dsp_encap_config: [4/1:1:32995] packet_len=30 channel_id=3 
packet_id=92 TransportProtocol 2 t_ssrc=0x0 r_ssrc=0x0 t_vpxcc=0x0 r_vpxcc=0x0
sid_support=1, tse_payload=65535, seq_num=0x0, redundancy=0
Jan 11 17:19:00.775: dsp_voice_mode: [4/1:1:32995] cdb 62DCEA70, 
cdb->codec_params.modem 2, inband_detect flags 0x21
Jan 11 17:19:00.775: map_dtmf_relay_type--digit relay mode: 2
Jan 11 17:19:00.775: dsp_voice_mode: [4/1:1:32995] packet_len=24 channel_id=3 
packet_id=73 coding_type=1 voice_field_size=160 VAD_flag=0 
echo_length=256 comfort
_noise=1 inband_detect=33 digit_relay_mode=2 
AGC_flag=0act_setup_ind_ack: modem_mode = 0, fax_relay_on = 1
Jan 11 17:19:00.775: act_setup_ind_ack(): dsp_dtmf_mode()
 dsp_dtmf_mode(VTSP_TONE_DTMF_MODE)

Jan 11 17:19:00.775: dsp_dtmf_mode: [4/1:1:32995] packet_len=10 channel_id=3 
packet_id=65 dtmf_or_mf=0
Jan 11 17:19:00.775: vtsp_timer: 31305236
Jan 11 17:19:00.775: vtsp:[4/1:1:32995, S_DIGIT_COLLECT, E_CC_GEN_TONE]
Jan 11 17:19:00.775: act_gen_tone
Jan 11 17:19:00.775: dsp_cp_tone_off: [4/1:1:32995] packet_len=8 channel_id=3 
packet_id=71
Jan 11 17:19:00.775: dsp_cp_tone_on: [4/1:1:32995] packet_len=38 channel_id=3 
packet_id=72 tone_id=4 n_freq=2 freq_of_first=350 freq_of_second=440 
amp_of_first=5514 amp_of_second=5514 direction=1 on_time_first=65535 
off_time_first=0 on_time_second=0 off_time_second=0
Jan 11 17:19:00.775: vtsp:[4/1:1:32995, S_DIGIT_COLLECT, E_CC_GEN_TONE]
Jan 11 17:19:00.775: act_gen_tone
Jan 11 17:19:00.775: dsp_cp_tone_off: [4/1:1:32995] packet_len=8 channel_id=3 
packet_id=71
Jan 11 17:19:00.775: dsp_cp_tone_on: [4/1:1:32995] packet_len=38 channel_id=3 
packet_id=72 tone_id=4 n_freq=2 freq_of_first=350 freq_of_second=440 
amp_of_first=
5514 amp_of_second=5514 direction=1 on_time_first=65535 off_time_first=0 
on_time4_second=0 off_time_second=0
Jan 11 17:19:00.775: htsp_process_event: [4/1:1(10), EM_WAIT_SETUP_ACK, 
E_HTSP_SETUP_ACK]em_wait_setup_ack_get_ack 
Jan 11 17:19:00.775: htsp_timer_stop 
Jan 11 17:19:00.775: htsp_timer2 - 172 msec
Jan 11 17:19:00.947: htsp_process_event: [4/1:1(10), EM_WAIT_SETUP_ACK, 
E_HTSP_EVENT_TIMER2]em_wait_prewink_timer 
Jan 11 17:19:00.947: em_offhook (0)[recEive and transMit4/1:1(10)] set signal st
ate = 0x8em_onhook (200)[recEive and transMit4/1:1(10)] set signal state = 0x0

!--- A wink of duration 200 msec is sent out to the switch.

Jan 11 17:19:01.471: vtsp_process_dsp_message: MSG_TX_DTMF_DIGIT_BEGIN: digit=9,
rtp_timestamp=0xED31C493

Jan 11 17:19:01.471: vtsp:[4/1:1:32995, S_DIGIT_COLLECT, E_DSP_DTMF_DIGIT_BEGIN]
Jan 11 17:19:01.471: act_report_digit_begin 
Jan 11 17:19:01.471: cc_api_call_digit_begin (dstVdbPtr=0x0, dstCallId=0xFFFFFFF
F, srcCallId=0x80E3,
digit=9, digit_begin_flags=0x1, rtp_timestamp=0xED31C493 
rtp_expiration=0x0, dest_mask=0x1)
Jan 11 17:19:01.471: sess_appl: ev(10=CC_EV_CALL_DIGIT_BEGIN), cid(32995), disp(0)
Jan 11 17:19:01.471: cid(32995)st(SSA_CS_MAPPING)ev(SSA_EV_DIGIT_BEGIN)
oldst(SSA_CS_MAPPING)cfid(-1)csize(0)in(1)fDest(0)
Jan 11 17:19:01.471: ssaIgnore cid(32995), st(SSA_CS_MAPPING),oldst(0), ev(10)
Jan 11 17:19:01.503: vtsp_process_dsp_message: MSG_TX_DTMF_DIGIT_OFF: 
digit=9, duration=65
Jan 11 17:19:01.503: vtsp:[4/1:1:32995, S_DIGIT_COLLECT, E_DSP_DTMF_DIGIT]
Jan 11 17:19:01.503: act_report_digit_end 
Jan 11 17:19:01.503: vtsp_timer_stop: 31305308
Jan 11 17:19:01.503: dsp_cp_tone_off: [4/1:1:32995] packet_len=8 channel_id=3 pa
cket_id=71
Jan 11 17:19:01.503: cc_api_call_digit_end (dstVdbPtr=0x0, dstCallId=0xFFFFFFFF,
srcCallId=0x80E3,
digit=9,duration=65,xruleCallingTag=0,xruleCalledTag=0, dest_mask=0x1), digi
t_tone_mode=0
Jan 11 17:19:01.503: htsp_digit_ready: digit = 39
Jan 11 17:19:01.503: vtsp_timer: 31305308
Jan 11 17:19:01.503: htsp_process_event: [4/1:1(10), 
EM_OFFHOOK, E_VTSP_DIGIT]em_offhook_digit_collect 
Jan 11 17:19:01.503: sess_appl: ev(9=CC_EV_CALL_DIGIT_END), cid(32995), disp(0)
Jan 11 17:19:01.503: cid(32995)st(SSA_CS_MAPPING)ev(SSA_EV_CALL_DIGIT)
oldst(SSA_CS_MAPPING)cfid(-1)csize(0)in(1)fDest(0)
Jan 11 17:19:01.503: ssaDigit
Jan 11 17:19:01.503: ssaDigit, 0. sct->digit , sct->digit len 0, 
usrDigit 9, digit_tone_mode=0
Jan 11 17:19:01.503: ssaDigit,1. callinfo.called , digit 9, 
callinfo.calling , x
rulecallingtag 0, xrulecalledtag 0
Jan 11 17:19:01.503: ssaDigit, 7. callinfo.calling , sct->digit 9, result 1
Jan 11 17:19:01.603: vtsp_process_dsp_message: MSG_TX_DTMF_DIGIT_BEGIN: 
digit=1, rtp_timestamp=0xED31C493

Jan 11 17:19:01.603: vtsp:[4/1:1:32995, S_DIGIT_COLLECT, E_DSP_DTMF_DIGIT_BEGIN]
Jan 11 17:19:01.603: act_report_digit_begin 
Jan 11 17:19:01.603: cc_api_call_digit_begin (dstVdbPtr=0x0, 
dstCallId=0xFFFFFFF
F, srcCallId=0x80E3,
digit=1, digit_begin_flags=0x1, rtp_timestamp=0xED31C493 rtp_expiration=0x0, 
dest_mask=0x1)
Jan 11 17:19:01.603: sess_appl: ev(10=CC_EV_CALL_DIGIT_BEGIN), cid(32995), 
disp(0)
Jan 11 17:19:01.603: cid(32995)st(SSA_CS_MAPPING)ev(SSA_EV_DIGIT_BEGIN)
oldst(SSA_CS_MAPPING)cfid(-1)csize(0)in(1)fDest(0)
Jan 11 17:19:01.603: ssaIgnore cid(32995), st(SSA_CS_MAPPING),oldst(0), ev(10)
Jan 11 17:19:01.643: vtsp_process_dsp_message: MSG_TX_DTMF_DIGIT_OFF: 
digit=1, duration=75
Jan 11 17:19:01.643: vtsp:[4/1:1:32995, S_DIGIT_COLLECT, E_DSP_DTMF_DIGIT]
Jan 11 17:19:01.643: act_report_digit_end 
Jan 11 17:19:01.643: vtsp_timer_stop: 31305322
Jan 11 17:19:01.643: cc_api_call_digit_end (dstVdbPtr=0x0, 
dstCallId=0xFFFFFFFF,
srcCallId=0x80E3,
digit=1,duration=75,xruleCallingTag=0,xruleCalledTag=0, 
dest_mask=0x1), digit_tone_mode=0
Jan 11 17:19:01.643: htsp_digit_ready: digit = 31
Jan 11 17:19:01.643: vtsp_timer: 31305322
Jan 11 17:19:01.643: htsp_process_event: [4/1:1(10), 
EM_OFFHOOK, E_VTSP_DIGIT]em_offhook_digit_collect 
Jan 11 17:19:01.643: sess_appl: ev(9=CC_EV_CALL_DIGIT_END), cid(32995), disp(0)
Jan 11 17:19:01.643: cid(32995)st(SSA_CS_MAPPING)ev(SSA_EV_CALL_DIGIT)
oldst(SSA_CS_MAPPING)cfid(-1)csize(0)in(1)fDest(0)
Jan 11 17:19:01.643: ssaDigit
Jan 11 17:19:01.643: ssaDigit, 0. sct->digit 9, sct->digit 
len 1, usrDigit 1, digit_tone_mode=0
Jan 11 17:19:01.643: ssaDigit,1. callinfo.called , digit 91, callinfo.calling , 
xrulecallingtag 0, xrulecalledtag 0
Jan 11 17:19:01.643: ssaDigit, 7. callinfo.calling , sct->digit 91, result 1
Jan 11 17:19:01.743: vtsp_process_dsp_message: 
MSG_TX_DTMF_DIGIT_BEGIN: digit=8, rtp_timestamp=0xED31C493

Jan 11 17:19:01.743: vtsp:[4/1:1:32995, S_DIGIT_COLLECT, 
E_DSP_DTMF_DIGIT_BEGIN]
Jan 11 17:19:01.743: act_report_digit_begin 
Jan 11 17:19:01.743: cc_api_call_digit_begin (dstVdbPtr=0x0, 
dstCallId=0xFFFFFFF
F, srcCallId=0x80E3,
digit=8, digit_begin_flags=0x1, rtp_timestamp=0xED31C493
rtp_expiration=0x0, dest_mask=0x1)
Jan 11 17:19:01.743: sess_appl: ev(10=CC_EV_CALL_DIGIT_BEGIN), cid(32995), 
disp(0)
Jan 11 17:19:01.743: cid(32995)st(SSA_CS_MAPPING)ev(SSA_EV_DIGIT_BEGIN)
oldst(SSA_CS_MAPPING)cfid(-1)csize(0)in(1)fDest(0)
Jan 11 17:19:01.743: ssaIgnore cid(32995), st(SSA_CS_MAPPING),oldst(0), ev(10) 
radius_decrypt: null length 
Jan 11 17:19:01.843: vtsp_process_dsp_message: MSG_TX_DTMF_DIGIT_OFF: 
digit=8, duration=75
Jan 11 17:19:01.843: vtsp:[4/1:1:32995, S_DIGIT_COLLECT, E_DSP_DTMF_DIGIT]
Jan 11 17:19:01.843: act_report_digit_end 
Jan 11 17:19:01.843: vtsp_timer_stop: 31305342
Jan 11 17:19:01.843: cc_api_call_digit_end (dstVdbPtr=0x0, dstCallId=0xFFFFFFFF,
srcCallId=0x80E3,
digit=8,duration=75,xruleCallingTag=0,xruleCalledTag=0, dest_mask=0x1), digi
t_tone_mode=0
Jan 11 17:19:01.843: htsp_digit_ready: digit = 38
Jan 11 17:19:01.843: vtsp_timer: 31305342
Jan 11 17:19:01.843: htsp_process_event: [4/1:1(10), 
EM_OFFHOOK, E_VTSP_DIGIT]em_offhook_digit_collect 
Jan 11 17:19:01.843: sess_appl: ev(9=CC_EV_CALL_DIGIT_END), cid(32995), disp(0)
Jan 11 17:19:01.843: cid(32995)st(SSA_CS_MAPPING)ev(SSA_EV_CALL_DIGIT)
oldst(SSA_CS_MAPPING)cfid(-1)csize(0)in(1)fDest(0)
Jan 11 17:19:01.843: ssaDigit
Jan 11 17:19:01.843: ssaDigit, 0. sct->digit 91, sct->digit len 2, usrDigit 8, d
igit_tone_mode=0
Jan 11 17:19:01.843: ssaDigit,1. callinfo.called , digit 918, callinfo.calling ,
xrulecallingtag 0, xrulecalledtag 0
Jan 11 17:19:01.843: ssaDigit, 7. callinfo.calling , sct->digit 918, result -1
Jan 11 17:19:01.843: ccCallDisconnect (callID=0x80E3, cause=0x1C tag=0x0)
Jan 11 17:19:01.843: vtsp:[4/1:1:32995, S_DIGIT_COLLECT, E_CC_DISCONNECT]
Jan 11 17:19:01.843: act_pre_con_disconnect 
Jan 11 17:19:01.843: vtsp_ring_noan_timer_stop: 31305342
Jan 11 17:19:01.843: dsp_cp_tone_off: [4/1:1:32995] packet_len=8 channel_id=3 pa
cket_id=71
Jan 11 17:19:01.843: dsp_voice_mode: [4/1:1:32995] cdb 62DCEA70, cdb->codec_para
ms.modem 2, inband_detect flags 0x21
Jan 11 17:19:01.843: map_dtmf_relay_type--digit relay mode: 2
Jan 11 17:19:01.843: dsp_voice_mode: [4/1:1:32995] packet_len=24 channel_id=3 pa
cket_id=73 coding_type=1 voice_field_size=160 VAD_flag=0 echo_length=256 comfort
_noise=1 inband_detect=33 digit_relay_mode=2 AGC_flag=0
Jan 11 17:19:01.843: dsp_cp_tone_on: [4/1:1:32995] packet_len=38 channel_id=3 pa
cket_id=72 tone_id=3 n_freq=2 freq_of_first=480 freq_of_second=620amp_of_first=
5206 amp_of_second=2928 direction=1 on_time_first=250 off_time_first=250 
on_time_second=0 off_time_second=0
Jan 11 17:19:01.843: vtsp_timer: 31305342
Jan 11 17:19:01.843: htsp_pre_connect_disconnect, cdb = 62DCEA70 cause = 1C

!--- Since the call is disconnected because the number received  is "unassigned" 
!--- or "invalid" the router  starts to play the reorder 
!--- tone and a timer, which is the wait-release
!--- timeout timer, starts with default 30 seconds. 
!--- This call is disconnected 
!--- prior to the connect state.

Jan 11 17:19:01.843: htsp_process_event: [4/1:1(10), EM_OFFHOOK, 
E_HTSP_PRE_CONN_DISC]
Jan 11 17:19:31.844: vtsp_main: timer: 31308342

!--- The wait-release timer expires after 30 seconds.

Jan 11 17:19:31.844: vtsp:[4/1:1:32995, S_WAIT_RELEASE_NC, E_TIMER]

!--- The VTSP module is in a wait release state for that call. It also receives 
!--- event timer, which means that the timer expires so that it 
!--- goes into another state.

Jan 11 17:19:31.844: act_pre_con_disc_rel htsp_release_req: cause 28, no_onhook 
0
Jan 11 17:19:31.844: htsp_process_event: [4/1:1(10), EM_OFFHOOK, 
E_HTSP_RELEASE_REQ]em_offhook_release 
Jan 11 17:19:31.844: htsp_timer_stop2 em_onhook (0)[recEive and transMit4/1:1(10
)] set signal state = 0x0
Jan 11 17:19:31.844: htsp_timer_stop 
Jan 11 17:19:31.844: em_start_timer: 400 ms 
Jan 11 17:19:31.844: htsp_timer - 400 msec

!--- HTSP receives an event  that requests the release of 
!--- the time slot and it goes into EM wait 
!--- onhook state. But, it cannot do anything since it says I am onhook already. 
!--- Also, the router starts a timer of 400 msec.

Jan 11 17:19:32.296: htsp_process_event: [4/1:1(10), EM_WAIT_ONHOOK, 
E_HTSP_EVENT_TIMER]em_wait_timeout 
Jan 11 17:19:32.296: em_stop_timers 
Jan 11 17:19:32.296: htsp_timer_stop 
Jan 11 17:19:32.296: em_start_timer: 400 ms 
Jan 11 17:19:32.296: htsp_timer - 400 msec

!--- When the 400 msec timer expires, HTSP gets into EM clear pending state. 
!--- It also starts another timer of 400 msec.

Jan 11 17:19:32.696: htsp_process_event: [4/1:1(10), EM_CLR_PENDING, 
E_HTSP_EVENT_TIMER]em_clr_timeout 
Jan 11 17:19:32.696: em_stop_timers 
Jan 11 17:19:32.696: htsp_timer_stop 
Jan 11 17:19:32.696: em_start_timer: 10000 ms 
Jan 11 17:19:32.696: htsp_timer - 10000 msec
Jan 11 17:19:32.700: htsp_dsp_message: SEND/RESP_SIG_STATUS: 
state=0xC timestamp=1533 systime=31308428
Jan 11 17:19:32.700: htsp_process_event: [4/1:1(10), EM_PARK, 
E_DSP_SIG_1100]em_park_offhook

!--- When the 400 msec timer expires, the router puts the time slot into 
!--- the EM_PARK state, and it starts another timer of 10 seconds. 
!--- The router  still sees the ABCD=1100 from the switch.

Jan 11 17:19:42.760: htsp_process_event: [4/1:1(10), 
EM_PARK, E_HTSP_EVENT_TIMER]em_park_timerhtsp_report_onhook_sig
Jan 11 17:19:42.760: em_offhook (0)[recEive and transMit4/1:1(10)] set signal st
ate = 0x8em_onhook (1000)[recEive and transMit4/1:1(10)] set signal state = 0x0
Jan 11 17:19:42.760: htsp_timer2 - 300000 msec
Jan 11 17:19:42.760: htsp_process_event: [4/1:1(10), 
EM_PARK, E_HTSP_EVENT_TIMER]em_park_timerhtsp_report_onhook_sig
Jan 11 17:19:42.760: em_offhook (0)[recEive and transMit4/1:1(10)] 
set signal state = 0x8em_onhook (1000)[recEive and
transMit4/1:1(10)] set signal state = 0x0
Jan 11 17:19:42.760: htsp_timer2 - 300000 msec

!--- As seen from the timestamps, when the timer expires in ten seconds,
!--- the router goes offhook for one second (1000 msec) and then onhook. 
!--- It also starts another timer of 300000 msec (5 minutes).

Reference:

http://www.cisco.com/en/US/tech/tk652/tk653/technologies_tech_note09186a0080112323.shtml