dltu การใช้

• Peripheral units are on shelves in the SM . In most exchanges the majority are Line Units ( LU ) and Digital Line Trunk Units ( DLTU ).
• T-carrier spans are terminated, originally one per card but in later models usually two, in Digital Line Trunk Units ( DLTU ) which concentrate their DS0 channels into the TSI . These may serve either interoffice trunks or, using Integrated Subscriber Loop Carrier, subscriber lines.