For example, digital echo cancellers were added to long-haul circuits, and transport channels were shaped to improve modem performance.
And, following Moore’s Law, PC capacity continues to double every 18 months, while the MIPS required to process a call’s media stream have remained relatively constant.
[1] It was quickly adopted as a generic term for software-based telephony products, used by many companies including Aculab, Pika, Eicon Networks, Uniqall, Commetrex, and NMS.
The concept of using an industry standard PC to do telephony processing is now widely understood and accepted, with open-source platforms like Asterisk, YATE and FreeSWITCH using the same principle.
Transformation includes the processing required to send or receive a fax and to transcode the stream from one speech codec to another for capability matching or bandwidth reduction.
There is an Internet Engineering Task Force (IETF) “RFC” (2833) [2] that defines how a gateway can perform the in-band-tone analysis to extract some of the embedded information, such as DTMF and caller ID.
This means no AGC, volume control, time-scale modification (playback speedup and slowdown), or capabilities matching with endpoint terminals, making this type of so-called HMP media server a viable option only in the most functionally constrained applications.