REST methods, available when working with Telephony (telephony scope).
When using this REST API and a set of interfaces, telephony operator can create his/her own application that will allow a transparent integration with Bitrix24 account. There are two options for telephony integration - use of REST API with an integral telephony (voixplant), as well as universal REST API option for telephony (telephony).
Client won't have to read manuals on configuration to sort out, how it works. Instead the client will get a readymade solution from the Marketplace and will continue to use the telephony in the most suitable environment - Bitrix24 service.