Reg. Asterisk service down suddenly

Hi,

i have asterisk 1.2.7.1. it is working fine.Suddenly the service was down, i was trying to connect asterisk -vvvvvvvvvvr, it said unable to connect… so i restarted the system and started working…Please find log

Aug 23 17:11:46 WARNING[5166] channel.c: Avoided initial deadlock for ‘0x9882860’, 10 retries!
Aug 23 17:19:29 WARNING[21832] app.c: No audio available on SIP/212-f26d??
Aug 23 17:23:13 WARNING[21933] res_features.c: Bridge failed on channels SIP/235-46fb and Zap/21-1
Aug 23 18:04:09 WARNING[5166] channel.c: Avoided initial deadlock for ‘0xb713c0d0’, 10 retries!
Aug 23 18:08:52 NOTICE[22612] callerid.c: Caller*ID failed checksum
Aug 23 18:08:52 NOTICE[22612] chan_zap.c: Got event 18 (Ring Begin)…
Aug 23 18:08:52 NOTICE[22612] chan_zap.c: Got event 17 (Polarity Reversal)…
Aug 23 18:08:52 NOTICE[22612] chan_zap.c: Got event 2 (Ring/Answered)…
Aug 23 18:08:55 NOTICE[22612] chan_zap.c: Got event 18 (Ring Begin)…
Aug 23 18:09:39 WARNING[22612] app_meetme.c: Failed to write audio data to conference: Bad file descriptor
Aug 23 18:11:20 WARNING[22612] app_meetme.c: Failed to write audio data to conference: Bad file descriptor
Aug 23 18:11:20 WARNING[22612] app_meetme.c: Conference not found
Aug 23 18:33:42 NOTICE[4950] cdr.c: CDR simple logging enabled.

i was to came to know at 18.30 , the service done, so i looged and restared the system and service and started working fine…

Even i have check the system log, system has not got rebooted once it own or by manual…

i shall be thankfull, if some one can throw your inputs to find out and to fix the issue…

Thanks in advance

i am unable to find the issue… why it had happend…

Any help would be appreciated…

Thanks in advance

Any help would be appreciated…

Thanks in advance

might be a zaptel issue, try restarting zaptel?
if you are using redhat style initscripts,

service asterisk stop
service zaptel stop
service zaptel start
service asterisk start
and see if that fixes it…