Client configured a UC520 with the CCA and it has listed dial-peers with destination patterns of A0 through A7.  Can anyone tell me what exactly this represents?  Their outbound calls are failing:

dial-peer voice 54 pots
description ** FXO pots dial-peer **
destination-pattern A0
port 0/1/0
no sip-register
!
dial-peer voice 55 pots
description ** FXO pots dial-peer **
destination-pattern A1
port 0/1/1
no sip-register
!
dial-peer voice 56 pots
description ** FXO pots dial-peer **
destination-pattern A2
port 0/1/2
no sip-register
!
dial-peer voice 57 pots
description ** FXO pots dial-peer **
destination-pattern A3
port 0/1/3
no sip-register
!
dial-peer voice 104 pots
description ** FXO pots dial-peer **
destination-pattern A4
port 0/2/0
no sip-register
!
dial-peer voice 105 pots
description ** FXO pots dial-peer **
destination-pattern A5
port 0/2/1
no sip-register
!
dial-peer voice 106 pots
description ** FXO pots dial-peer **
destination-pattern A6
port 0/2/2
no sip-register
!
dial-peer voice 107 pots
description ** FXO pots dial-peer **
destination-pattern A7
port 0/2/3
no sip-register