increased in a multi unit system the scan periods are offset from an absolute time reference to prevent more than one unit from transmitting at the same time application_number US 66750500 A description in the following description the invention is described in terms of a bluetooth communication system but it will be understood that applicant 39 s invention is not so limited the invention is broadly applicable to peer to peer communication networks and can be embodied in other types of communication systems that have appropriate features fig1 depicts a timing diagram of an ideal slotted packet based radio interface between two peer units a and b packets 100 start at a slot boundary 102 and can last for a generally unrestricted period of time 104 as shown in fig1 unit a transmits packet 100 a beginning at slot boundary 102 a and lasting for a duration 104 a likewise packet 100 b begins at slot boundary 102 b and lasts for a duration 104 b in this example packet 100 b has a shorter duration than packet 100 a as can be appreciated unit b transmits its packets 100 e 100 f 100 g and 100 h beginning at respective slot boundary 102 e 102 f 102 g and 102 h by design unit a and unit b do not transmit at the same time bluetooth implements a variation of this type of channel in which the packet length can vary and the packet can occupy between one and five slots preferably a priority scheme exists among the units so that each unit knows when it is permitted to transmit on the channel such a scheme is.