In nowadays Voice over Internet Protocol (VoIP) stays mainstream technology for providing flexible service for user communication and integration with all other systems like CRM or any.
It can be hardware ready setup like Yeastar, or software like Asterisk, Elastix, 3СХ.
Today we have many cloud-based PBX services
Also we can provide maintaining services for old analog telephony systems like Panasonic (TEB, TES, etc) and LG Nortel
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