Voip telephony is picking up very fast.  Almost all corporates are now using IP phones for their internal communication. Soft switches are capturing the PBX market. So the market for IP phones are increasing at a rapid rate. Embedded linux platforms suit IP phones as the linux OS provides almost everything needed for an IP phone. Ethernet connectivity, multimedia drivers etc are part of linux OS. Many linux  SBCs are available in the configuration needed for an IP phone. And IP phone running asterisk can even act as a local PBX. With opensource software and low cost SBCs, IP phones can be manufactured sub 100$ mark. In bulk production even the 100$ mark can be brought down.