Connecting  Tx/Rx to Baycom Packet Radio Modem

Hi, I'm trying to make a connection between two arduinos with packet-radiomodem Baycom based on TCM 3105NL Texas Instrument CI.

For that, previously I convert ttl to rs232 with MAX-232, but I saw a circuit using ds14c232 (a TIA/EIA 232 Dual Receiver).

Any idea?