Circuit Switched Data Service

Get the Flexibility, Security, and Reliability Your Agency Deserves

This product is only available under the Universal contract.

CenturyLink® Circuit Switched Data Service (CSDS) gives your Agency end-to-end, digital circuit-switched communication. The ease of use and "pay as you go" pricing puts your Agency in charge. With CenturyLink® CSDS, Agency end users can dial-up in 56 Kbps or 64 Kbps increments of digital bandwidth, up to a full switched T-1 (equivalent to 1.536 Mbps). By allowing access through switched or dedicated facilities, CenturyLink® CSDS provides your Agency flexibility and an increased service coverage area. Additionally, your agency will get a delivery approach designed to provide a highly efficient, flexible service that supports all of your agency's functional requirements.


  • Uniform numbering plan
  • Authorization codes
  • Reservationless calling capability
  • Provision of network-derived clocking to the Data Termination Equipment (DTE) or PBX/Multiplexer (MUX) at the Service Delivery Point
  • Following call establishment, all bit sequences transmitted by the DTE are transported as data/bit transparent and maintain data/bit sequence integrity
  • Multiple categories (DS0, DS1, and Multirate DSO) of dialable information-payload bandwidth

CenturyLink® CSDS connects to and interoperates with a variety of switched data compatible equipment. These include PBX and Video Codec gear, in addition to the Public Switched Telephone Network and CSDS carriers' networks. CenturyLink® CSDS is delivered through a combination of different service elements, including access, transport, Service Enabling Device (SED), and features.

  • Access can be either switched (off-net) or dedicated (on-net). CenturyLink provides CSDS access arrangements to meet your Agency's diverse requirements. User Network Interface (UNI)/SEDs connect to circuit switched, wireless and broadband wireless access
  • Transport and signaling infrastructure is engineered in a diverse and redundant fashion to provide your agency robust and reliable service
  • CSDS UNIs and SEDs with speeds up to 1536 Kbps CSDS SEDs are customized depending on the access method or selected feature, such as the CSDS required support for RS366 signaling. RS366-capable SEDs have two physical ports for customer connections (one port for data traffic and one port for signaling)
  • Features also include the capability to support Dial–In


  • Cost efficiencies – Your Agency can do more for less
  • Maximum application flexibility – Easily changes to meet your agency's changing needs
  • Cost management – Know exactly what your agency's costs are
  • Inexpensive access – Get more done for less


Supports data backup applications, as well as H.320 video services

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