dect modes associated with the dual band first local oscillator there are band control means operable to adjust the local oscillator frequency in response to channel detection means which detect the channel employed in any communication in the case of the mobile initiating a call then the channel detection means will be able to detect which channels are available and be able to effect the control switches for the dcs1800 dect circuits as appropriate the programmable dividers operate under the control of data clock and enable commands the prime second local oscillator 2lo produces a two frequencies at 450 and 442 368 mhz and employs a feedback path to ensure that the frequency is maintained by these means the required frequencies 225 130 and 110 592 mhz can be derived from the 13 0 and 13 824 mhz references as can the required first local oscillator frequencies the synthesised first local oscillator accomplishes dual mode operation by having a dual band local oscillator which tunes dual bands 1580 to 1655 mhz for dcs1800 or 1771 200 to 1786 752 mhz for dect in the dcs1800 mode the 1lo tunes in 200 khz spaced channels and in the dect mode 1 728 mhz spaced channels defined by the by r.