SMA Features: Provides five multiple access return channels and one multiple access forward channel per spacecraft. Includes return service , which uses the same frequency (i.e. 226.5 MHz) and CDMA to avoid interference. TDRS Trio For TDRS-HI, -I, -J the return has been increased to 3 Mbps , as opposed to 100 Kbps of the previous TDRS . Upgraded to 300 Kbps . TDRS provides trio services such as S-Band Multiple Access Services as well as SD-Band Single Access (SSA) and Ku-Band Single Access ( KUSA) .