Because RFL™ and Hubbell® have a policy of continuous product improvement, we reserve the right to change designs and specifications without notice.
2.3.3.10 Fast Reframe Channel
Fast Reframe Channel is a function that can be selected by the user via toggle switches on the front
panel of the CM4 module, or via the NMS. This function can be either “on” or “off ”. When off, the
fast reframe function is not used and time slot 30 is available for user payload data. When on, the
reframe time is less than 400μs. This pertains only to FAS framing, i.e., on a single-frame basis. The
multiframe structure of the E1 signal will be synchronized within the time frame required for CRC4
and CAS framing.
When the Fast Reframe Channel is on, time slot 30 of the E1 packet is devoted to monitoring the
synchronization of the E1 data and verifying that the data is being received correctly. It does this by
sending a repetitive 8-bit test pattern. If the test pattern is not received correctly, this indicates a loss
of framing. The CM4 module is able to detect this pattern and reframe the E1 data.
Data traffic relying only on a single-frame structure such as digital communications or tone protection
will benefit from the fast reframe function. Fast reframe will not improve synchronization times for
traffic utilizing a multi-frame structure such as CAS signaling.
When Fast Reframe is set to off, the system is in normal reframing mode. Normal reframing mode is
usually used for voice communications, however with data communications fast reframing is usually
used.
IMUX 2000E1 RFL Electronics Inc.
April 1, 2007 2-15 (973) 334-3100
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