olemus
ISO/IEC 2382:
kahesuunalise andmeedastuse kanalite paar,
võib sisaldada lõppseadmeid
= pair of associated transmission channels that provides a means of two-way data transmission



ülevaateid
http://what-when-how.com/data-communications-and-networking/circuits-data-communications-and-networking/

https://www.neweggbusiness.com/smartbuyer/networking/which-type-of-data-circuit-is-right-for-your-business/

https://www.csus.edu/indiv/t/tsain/m214/rowe9.ppt

https://www.teracomtraining.com/tutorials/teracom-tutorial-data-circuit-model.htm