ADTRAN T200 H4TU-R Table A-2. Loopback Control Codes, Function Code Hex / Binary Response, H4TU-C

Table A-2. Loopback Control Codes

Function	Code (Hex / Binary)	Response
ARM (in-band) - also	11000 (binary)	If the pattern is sent from the network, the units will arm, and
known as 2-in-5 pattern		the H4TU-R will loop up if NIU Loopback is enabled.
ARM (ESF Data Link)	FF48 or	If the pattern is sent from the network, the units will arm, and
	1111 1111 0100 1000	the H4TU-R will loop up if NIU Loopback is enabled. When
	sent in the Facility Data Link	sent from the customer, the units will arm.
Disarm (in-band) - also	11100 (binary)	When sent from the network or customer, all units are
known as 3-in-5 pattern		removed from the armed state, and loopbacks will be released.
Disarm (ESF Data Link)	FF24 or	When sent from the network or customer, all units are
	1111 1111 0010 0100	removed from the armed state, and loopbacks will be released.
	sent in the Facility Data Link
H4TU-C Loop Up 1,2	D3D3 or	If armed, the H4TU-C will loop up, 2 seconds of AIS (all
	1101 0011 1101 0011	ones) will be transmitted, the looped data will be sent for 5
		seconds, and then a burst of 231 logic errors will be injected.
		The burst of 231 logic errors will continue every 20 seconds as
		long as the D3D3 pattern is detected. When the pattern is
		removed, the unit will remain in loopback. If the pattern is
		reinstated, the injection of 231 logic errors will continue every
		20 seconds.
Loop Down w/o Disarm	9393 or	When sent from the network, all units currently in loopback
	1001 0011 1001 0011	will loop down. Armed units will not disarm. In order to
		behave like a smartjack, the H4TU-R will not loop down from
		a network loopback in response to the 9393 pattern if NIU
		Loopback is enabled.
Loopback Query 1	D5D5 or	When the pattern is sent from the network, logic errors will be
	1101 0101 1101 0101)	injected toward the network to indicate a loopback is present
		toward the network. The number of errors injected is
		determined by the nearest unit that is in loopback. As long as
		the pattern continues to be sent, errors are injected again every
		20 seconds:
		H4TU-C	231 errors
		H4R1	10 errors
		H4R2	200 errors
		H4TU-R	20 errors
Loopback Time Out	D5D6 or	If the units are armed or a unit is currently in loopback when
Override1	1101 0101 1101 0110	this pattern is sent from the network, the loopback time out
		will be disabled. As long as the units remain armed, the time
		out will remain disabled. When the units are disarmed, the
		loopback time out will revert to the previous loopback time
		out setting.
		If any element is in network loopback a bit error confirmation
		will be sent.
		H4TU-C	231 errors
		H4R1	10 errors
		H4R2	200 errors
		H4TU-R	20 errors

61223424L2-5A Issue 1, December 2003 A-3