Interphase Tech iSPAN 5535 PRI - Manual (Page 81)

Chapter 5: Setting Up WAN Firmware and Hardware
iSPAN PRI PCI ISDN Users Guide 61
Facility Data Link
Protocol(s) Facility Data Link protocols are used to exchange
messages between the adapter and the remote end of the
network. Such messages are issued by the Telco to put
the adapter in loopback mode for testing when problems
occur. They are also used to transmit statistics about
physical transmission errors on the line.
Two protocols are available for the facility data link: the
ANSI-T1-403 and the ATT-54016 protocol. Both are
compatible with each other.
Use the protocol(s) indicated by your Telco. If this
information is unavailable, the best choice is to use both
protocols.
Option Description