參數(shù)資料
型號(hào)： T7230A
廠商： Lineage Power
元件分類(lèi)： 通信及網(wǎng)絡(luò)
英文描述： Ultraframer DS3/E3/DS2/E2/DS1/E1/DS0
中文描述： Ultraframer DS3/E3/DS2/E2/DS1/E1/DS0
文件頁(yè)數(shù)： 44/110頁(yè)
文件大小： 752K
代理商： T7230A
Preliminary Data Sheet
T7230A Primary Access Framer/Controller
June 1997
40
Lucent Technologies Inc.
Frame Formats
(continued)
CEPT Loss of CRC-4 Multiframe Alignment Recovery Algorithms
(continued)
CRC-4 Multiframe Alignment Search Algorithm with 400 ms Timer
This receive CRC-4 multiframe reframe mode is the modified CRC-4 multiframe alignment algorithm described in
ITU Rec. 706 Annex B, where it is referred to as CRC-4-to-Non-CRC-4 equipment interworking. A flow diagram of
this algorithm is illustrated in Figure 11. When the interworking algorithm is enabled, it supersedes the algorithm
described in option 2 above. This algorithm assumes that a valid basic frame alignment signal is consistently
present but the CRC-4 multiframe alignment cannot be achieved by the end of the total CRC-4 multiframe align-
ment search period of 400 ms, if the remote end is a non-CRC-4 equipment. In this mode, the following consequent
actions are be taken:
1.
An indication that there is no incoming CRC-4 multiframe alignment signal.
2.
CRC-4 data is transmitted to the distant end with both E bits set to zero.
This algorithm allows the identification of failure of CRC-4 multiframe alignment generation/detection, but with cor-
rect basic framing, when interworking between equipment each having the modified CRC-4 multiframe alignment
algorithm.
As described in ITU Rec. G.706 Section B.2.3:
1.
A 400 ms timer starts on the initial recovery of the primary basic frame alignment.
2.
The 400 ms timer reset if and only if:
A. The criteria for loss of basic frame alignment as described in ITU Rec. G.706 Section 4.1.1 is achieved.
B. If 915 out of 1000 errored CRC-4 blocks are detected resulting in a loss of basic frame alignment as
described in ITU Rec. G.706 Section 4.3.2.
C. On-demand reframe is requested.
D. The receive framer is programmed to the non-CRC-4 mode.
3.
The loss of basic frame alignment checking process runs continuously irrespective of the state of the CRC-4
multiframe alignment process below it.
4.
A new search for frame alignment is initiated if CRC-4 multiframe alignment cannot be achieved in 8 ms as
described in ITU Rec. G.706 Section 4.2. This new search for basic frame alignment will not reset the 400 ms
timer or invoke consequent actions associated with loss of the primary basic frame alignment. In particular, all
searches for basic frame alignment are carried out in parallel with, and independent of, the primary basic frame
loss checking process. All subsequent searches for CRC-4 multiframe alignment are associated with each
basic framing sequence found during the parallel search.
5.
During the search for CRC-4 multiframe alignment, traffic is allowed through upon, and synchronized to, the
initially determined primary basic frame alignment.
6.
Upon detection of the CRC-4 multiframe before the 400 ms timer elapsing, the basic frame alignment associ-
ated with the CRC-4 multiframe alignment replaces, if necessary, the initially determined basic frame align-
ment*.
7.
If CRC-4 multiframe alignment is not found before the 400 ms timer elapses, it is assumed that a condition of
interworking between equipment with and without CRC-4 capability exists and the actions described above are
taken.
8.
If the 2.048 Mbits/s path is reconfigured at any time, then it is assumed that the (new) pair of path terminating
equipment will need to re-establish the complete framing process, and the algorithm is reset.
* The basic frame may be aligned to the primary basic frame or may not be aligned to the primary basic frame. If the later, the new basic frame
alignment is forced and one frame of transmitted system data is corrupted.
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
T-7230A--ML 制造商:Rochester Electronics LLC 功能描述:- Bulk
T7230-ML3 制造商:AGERE 功能描述:
T7-231A1 功能描述:撥動(dòng)開(kāi)關(guān) ON NONE OFF 2 Pole Standard Bat Handle RoHS:否 制造商:OTTO 觸點(diǎn)形式: 開(kāi)關(guān)功能: 電流額定值: 電壓額定值 AC: 電壓額定值 DC: 功率額定值: 端接類(lèi)型: 安裝風(fēng)格: 端子密封: 觸點(diǎn)電鍍: 照明:
T7-231A2 制造商:OTTO Engineering Inc 功能描述:2POLE, SOLDER, STD,
T7-231A2D 功能描述:撥動(dòng)開(kāi)關(guān) ON NONE OFF 2 Pole Standard LeverLock RoHS:否 制造商:OTTO 觸點(diǎn)形式: 開(kāi)關(guān)功能: 電流額定值: 電壓額定值 AC: 電壓額定值 DC: 功率額定值: 端接類(lèi)型: 安裝風(fēng)格: 端子密封: 觸點(diǎn)電鍍: 照明:
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