Each frequency band (43-50 MHz, 900 MHz, 2.4 GHz or 5.8 GHz) can be subdivided into different increments or channels. For example, on some models, when you're talking on your 900 MHz phone, the base searches for a pair of frequencies (channels) within that range, that is not already in use, in order to talk to the handset. So, if the base is capable of searching more increments, it can more easily find a frequency pair that is clear from interference, providing better sound quality. The number of cordless phone channels can vary as follows:
10 to 25 channels - 43-50 MHz phones, some inexpensive 900 MHz phones
20 to 60 channels - most 900 MHz phones
50 to 100 channels - high-end 900 MHz and 2.4/5.8 GHz phones