If the remainer of the five-byte multinomial divided by x~8+x~2+x+1 is 0, the five-byte is a correct cell header. With the later 48 bytes, an ATM cell is formed.

• 信元定界的算法描述如下:RxSync通过连续的检测5个字节,若发现5个字节的多项式除以x~8+x~2+x+1后余0,则表明这5个字节就是信元头,再加上后面的48个字节就是一个ATM信元。