Packet is a generic word that define to small code of data. Packet have different format. Each hardware needs different packet format.
A hardware frame or frame shows a packet of a specific format on a specific Hardware method.
We require to describe a standard format for data to show the beginning and end of the frame. Tail and header are used to frame the data as given in the figure below.
We see that in the diagram eot and soh are used to show the start of header and end of tail.