Top: long-term photometric V and y data of IN Com. Different colours mean different sources of observations; green: data from T6 and T7 APTs, blue: observations from the Hungarian 1 m RCC telescope, red: literary data (mostly from Paper 1) that are used for seasonal period determination, grey: literary data+ASAS data that are not suitable for seasonal period determination. The sine-wave fit by black solid line represents the long-term overall brightness change with a period of 7.2 yr, which is basically the wide binary period (see Sect. 6). Bottom: independent rotational period determinations for suitable seasonal data sets. Further details can be found in the text.