电信专业英英词典S-2（在线收听）

　　Simple Network Management Protocol (SNMP)

　　SNMP is the application protocol offering network management service in the Internet suite of protocols. A structure for formatting messages and transmitting information between reporting devices (agents) and data collection programs. Developed jointly by the Department of Defense, industry and the academic community as part of the TCP/IP protocol suite; ratified as an Internet standard in Request for (Comment (RFC) 1098.

　　Simplex

　　Simplex is a transmission path capable of transmitting signals in only one direction.

　　Single Mode Optical Fiber(s)

　　Single mode optical fibers have sufficiently small core diameters in relation to the wavelength (frequency) of operation that electromagnetic (light) wave is constrained to travel in only one transverse path from transmitter to receiver. This requires the utmost in angular alignment of light emitting devices at points where light enters the fiber and results in higher transmitter/termination costs than multimode fiber systems. See multimode optical fiber(s).

　　SMDR

　　station message detail record

　　SMDS

　　switched multimegabit data system

　　SMT

　　station management technology

　　SNA

　　Systems Network Architecture

　　SNI

　　subscriber network interface

　　SNMP

　　Simple network management protocol. See Simple Network Management Protocol (SNMP).

　　SO

　　Service Order

　　SOC

　　Service Order Code

　　SONET

　　synchronous optical network

　　Space Division

　　Space division is a switch that implements the switch matrix using a physical, electrical, spatial link. Where older space division switches used electro-mechanical mechanisms with metallic contacts, modern space-division switches are implemented electronically using integrated circuits. (Usually denoted by "S" in combined time and space division switches).

　　Special Services

　　Special services are any of a variety of LEC and IXC switched, non-switched, or special rate services that are either separate from public telephone service or contribute to certain aspects of public telephone service. Examples include PBX tie trunks, foreign exchange (FX) and private line services. These services are important to business telecommunication planners/users.