Network managers have long awaited practical voice-over-IP (VOIP) solutions. VOIP promises ease network management and decreases (66) by converging a company’s telephony and data infrastructures into one network. And a VOIP solution implemented at a company’s head-quarters with far-reaching branch offices can (67) tremendous amounts of money in long distance phone bills, provided that solution delivers POTS-like voice (68) over the Internet.
VOIP gateways are designed to convert voice from the (69) domain to the circuit switched domain. VOIP solutions use a digital signal processor (DSP) to process the voice data, preparing the voice sample for transmission by compressing voice and removing jitter. The VOIP equipment must comply with the (70) H.323 standard defined by the International Telecommunication Union, or ITU.

A．framing

B．message

C．circuit

D．packet

肾结石的声像图表现为（）
肾钙乳症的声像图表现为（）
肾陈旧性改变（钙化）的声像图表现为（）
髓质海绵肾的声像图表现为（）

A.肾锥体回声增强，形似面团，呈放射状排列，可有细砂状强回声，颗粒排列其中

B.多个肾盏扩张，肾盏内可见可见细砂状强回声颗粒，改变体位可见"落雪征"

C.肾皮质、肾柱区强回声分布，其后可见声尾、声影表现

D.肾盏区可见多个强回声团，后方以声影为主

E.肾轮廓异常，肾区见多个囊泡状结构，囊壁可见小片状增强回声