Audio signal levels, transmission lines, Pull-up Pull-down Resistor

 ST1480A Series 3.3 V 15 kV ESD Protected RS-485/RS-422 Transceiver - SOIC-8

https://www.futureelectronics.com/p/semiconductors--signal-interface--line-driver-or-receiver/st1480abdr-stmicroelectronics-6127713