Simple way checking of E1 Vs TRX Mapping is E1 is 2Mbps links which is divided into 64KbpsX32 TSs,& each 64Kbps TS further divided into 16KbpsX4 nibbles,
so we can assume that 2Mbps link consist of =4*32=128 nibbles
While a TRX consist of 8 TS & each TS can be mapped one one Abis nibble.
so if we assume that 03 Abis TS are reserved for OM & Signalling purposes, then we have available Abis TSs=29 & nibbles are 29*4=116.
hence Max Possible TRXs on Abis = 116/8=14.5, i forgot how much TS required for RSLs 🙁