DS26401 datasheet(183/309 Pages) DALLAS

183 / 309 page

DS26401 Octal T1/E1/J1 Framer

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10.10.4 Signaling Debounce

When signaling integration is enabled the signaling data at RSIG is automatically debounced. Signaling must be

constant for three multiframes before being up-dated at RSIG. Signaling debounce is enabled on a global basis.

10.10.5 Receive Signaling Reinsertion at RSER

In this mode, the user will provide a multiframe sync at the RSYNC pin and the signaling data will be reinserted

based on this alignment. In T1 mode, this results in two copies of the signaling data in the RSER data stream. The

original signaling data based on the Fs/ESF frame positions and the realigned data based on the user supplied

multiframe sync applied at RSYNC. In voice channels this extra copy of signaling data is of little consequence. Re-

insertion can be avoided in data channels since this feature is activated on a per-channel basis. For reinsertion, the

elastic store must be enabled, however, the backplane clock can be either 1.544MHz or 2.048MHz.

Signaling reinsertion mode is enabled, on a per-channel basis by setting the Receive Signaling Re-insertion

Channel Select bit high in the RSI register. The channels that are to have signaling reinserted are selected by

writing to the RSI1-RSI4 registers. In E1 mode, the user will generally select all channels or none for reinsertion.

10.10.6 Receive Signaling Freeze

The signaling data in the four multiframe signaling buffer will be frozen in a known good state upon either a loss of

synchronization (OOF event), carrier loss, or change of frame alignment. To allow this freeze action to occur, the

RSFE control bit (RSIGC.1) should be set high. The user can force a freeze by setting the RSFF control bit

(RSIGC.2) high. The RSIGF output pin provides a hardware indication that a freeze is in effect. The four multiframe

buffer provides a three multiframe delay in the signaling bits provided at the RSIG pin (and at the RSER pin if

Receive Signaling Reinsertion is enabled). When freezing is enabled (RSFE = 1), the signaling data will be held in

the last known good state until the corrupting error condition subsides. When the error condition subsides, the

signaling data will be held in the old state for at least an additional 6ms before being allowed to be updated with new

signaling data.

DS26401 Datasheet(PDF) 183 Page - Dallas Semiconductor