Remote V54 loopback commands are intended to place compatible external equipment into a loopback state. The initiating unit will maintain normal data flows during these tests. (3) Transmit V54 loop up - commands the node to send a standard in-band loop up pattern towards the WAN per ITU V.54. This is a framed T1 signal consisting of a pseudorandom signal in place of all user data (that is only in the DS0s assigned to the DTE). A device terminating the fractional T1 data is expected to enter a bi-directional DTE Loopback condition upon recognition of this pattern. The initating unit doesn't know if the command was accepted by the remote unit. This pattern will not traverse a typical frame relay network and is designed for circuit-switched diagnostics. (4) Transmit V54 loop down - commands the node to send a standard in-band loop down pattern towards the WAN per ITU V.54. This is a framed T1 signal consisting of a pseudorandom signal in place of all user data (that is only in the DS0s assigned to the DTE). A device terminating the fractional T1 data is expected to clear a bi-directional DTE Loopback condition upon recognition of this pattern. The initating unit doesn't know if the command was accepted by the remote unit.