Because RFL™ and Hubbell® have a policy of continuous product improvement, we reserve the right to change designs and specifications without notice.
RFL DS-64NC RFL Electronics Inc.
August 1, 2007 51 (973) 334-3100
APPLICATION NOTE
DS-64NC (ASSEMBLY NO 9547-1686 REVISION F & G)
WHEN SUBJECTED TO INTERMITTENT TRAFFIC
The DS-64NC is designed to pass either continuous or burst type traffic in bi-directional and
unidirectional modes. Severe T1 disruptions can affect the software running on the receive DSP such
that the receive function may cease working until the DSP is rebooted. The latest version (revision F
and G) of the DS-64NC will perform this reboot function automatically if it senses that traffic has been
interrupted for more than 1.6 seconds. This prevents any permanent loss of traffic in the field. This
rebooting operation has consequences in two different applications:
The system may be set up for unidirectional operation. As one end of this type of system never sees
any traffic, the rebooting circuit would cause it to reboot approximately every 6 seconds. This is
undesirable as traffic in the other direction is momentarily lost. In this configuration, the mode
switches or NMS settings on the cards must be set for unidirectional use. The module that has its
receiver turned off (S3-6, see item 7 in Table 2) will not reboot. The other end will reboot correctly if
traffic is lost in that direction.
Some applications have traffic that, by it’s nature, has gaps longer than 1.6 seconds. This is typically
seen in MA-427 LAN systems providing Ethernet bridging. If a gap in traffic is long enough to cause
a reboot, it is possible to lose data sent during the reboot process. The automatic resend feature of
Ethernet will force the data to be resent and no traffic should be permanently lost.
During the reboot process, the LED’s on the front of the module flash. This is considered normal
operation.
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