and thus will only be described briefly herein ina is a method of unbundling ds0s into ina groups as d4 framed ds1s an ina group typically consists of between 1 and 28 ds1s ina is protocol supported so that a service provider can unbundle the loops to a channel bank to provide an analog handoff to an alternate service provider if required tr08 interface is an idlc configuration that is derived from lucent technologies slc96 dlc products tr08 mode 1 consists of four ds1s 96 ds0s that serve up to 96 lines with no concentration tr08 mode 2 uses two ds1s 48 ds0s that serve up to 96 lines providing 2 1 concentration a gr303 interface is an idlc configuration that is the successor to tr08 gr303 supports between 2 and 28 ds1s 1 to 2048 lines with up to 9 1 concentration two of the t1 links used in an interface group contain a timeslot management channel tmc used for call processing and an embedded operations channel eoc used for management each of these channels occupies a ds0 primary rate interface pri is an integrated services digital network isdn level of service typically used for connecting businesses with a central office e1 cas is a system in which control signals are transmitted in the same channel as the data and voice signals both the remote terminals and the host digital terminals further include a timeslot interchanger tsi the tsi is used for grooming.