I install fw and sangoma A101 card with sangoma isdn. after few days, caller can not 

hear the ring back tone, but the voice worked. the hardware is ok, compare with normal status, the alert message 

lost. how do i set that to enforce to send alert message?

Best regards,
James.zhu
Doing asterisk/PRI/ss7/dahdi, linux, asterisk/sangoma cards, recording device, VOIP gateway.
website: www.hiastar.com