IDD and DTM This topic has 0 replies, 1 voice, and was last updated 12 years, 1 month ago by pritam. Viewing 1 post (of 1 total) Author Posts 2nd March 2012 at 20:04 #67950 pritamGuest hi pix,wat is the use of IDD and DTM mode in gsm? Author Posts Viewing 1 post (of 1 total) The forum ‘Telecom Design’ is closed to new topics and replies.