Netopia 435 Reference Manual page 250

ISDN Events E-7
Cause No. 58: bearer capability not presently available. This
cause indicates that the user has requested a bearer capability
implemented by the equipment that generated this cause which is
not available at this time.
Cause No 63: service or option not available, unspecified. This
cause is used to report a service or option not available event only
when no other cause in the service or option not available class
applies.
Cause No. 65: bearer capability not implemented. This cause
indicates that the equipment sending this cause does not support
the bearer capability requested.
Cause No. 66: channel type not implemented. This cause
indicates that the equipment sending this cause does not support
the channel type requested.
Cause No. 69: requested facility not implemented. This cause
indicates that the equipment sending this cause does not support
the requested supplementary service.
Cause No. 70: only restricted digital information bearer capability
is available. This cause indicates that one equipment has
requested an unrestricted bearer service but the equipment
sending this cause only supports the restricted version of the
requested bearer capability.
Cause No. 79: service or option not implemented, unspecified.
This cause is used to report a service or option not implemented
event only when no other cause in the service or option not
implemented class applies.
Cause No. 81: invalid call reference value. This cause indicates
that the equipment sending this cause has received a message with
a call reference which is not currently in use on the user-network
interface.