Method of sending print data

A method of sending print data in a printing apparatus by a serial transfer method, comprising:

• generating a first data part with a fixed data length;
• generating a second data part with a variable data length;
• and
• combining the first data part and the second data part in a predetermined order to form resulting print data and sending the resulting print data, wherein
• the first data part includes a plurality of information pieces,
• the second data part is capable of including a plurality of additional information pieces,
• a first information piece being one of the plurality of information pieces included in the first data part indicates presence or absence of each of the plurality of additional information pieces in the second data part,
• a second information piece being one of the plurality of information pieces includes a plurality of pieces of synthesized data, and
• in the sending, the plurality of pieces of synthesized data are each subjected to bit division, and portions of the pieces of synthesized data subjected to the bit division which have a smaller bit length are continuously arranged in a single packet.