[Asterisk-Users] Phone_read Resource temporarily unavailable

[Jer]

Could someone tell me why I would get this using a linejack POTS

May 20 17:43:05 WARNING[1217602880]: chan_phone.c:417 phone_read: Error 
reading:
  Resource temporarily unavailable
May 20 17:43:05 WARNING[1217602880]: app_festival.c:181 
send_waveform_to_channel : Null frame == hangup() detected
May 20 17:43:05 WARNING[1217602880]: file.c:521 ast_readaudio_callback: 
Failed tto write frame

Thankyou