Erlang-B Calculation of TETRA System This topic has 0 replies, 1 voice, and was last updated 17 years, 4 months ago by carlo. Viewing 1 post (of 1 total) Author Posts 21st August 2007 at 05:51 #48945 carloGuest Dear all: How can I calculate the required E1 lines in the tetra system? including the PABX lines with it. Will anybody explain me how? Thanks. Author Posts Viewing 1 post (of 1 total) The forum ‘Telecom Design’ is closed to new topics and replies.