olemus
asutusesisene välisvõrguga ühendatud telefonijaam/-süsteem

Wiktionary:
(telecommunications) a telecommunications switching system, physically located at a customer's place of business, that provides internal communication between users and also access to outside (trunk) telephone lines

ülevaateid
https://www.techopedia.com/definition/8807/private-branch-exchange

https://en.wikipedia.org/wiki/Business_telephone_system#Private_branch_exchange

https://www.ecn.co.za/how-many-types-of-pbx-are-there/

https://www.nextiva.com/blog/pbx-vs-voip.html

turvalisus
http://www.tscm.com/NISTsp800-24pbx.pdf

https://conference.hitb.org/hitbsecconf2007dubai/materials/D2%20-%20David%20Michaux%20-%20Telecom%20Fraud.pdf

http://i3forum.org/wp-content/uploads/2017/01/Best_practice_for_common_IP_PBX_security_breaches-I3-Forum_V2.pdf

https://blog.kolmisoft.com/pbx-security-best-practices/

https://www.ipcomms.net/64-news/298-11-ways-to-secure-your-ip-pbx

vt ka
- IP-kodukeskjaam