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  DS1
       
           A DS level and framing specification for
          synchronous digital streams, over circuits in the North
          American digital transmission hierarchy, at the T1
          transmission rate of 1,544,000 bits per second ({baud).
       
          DS1 is commonly used to multiplex 24 DS0 channels.  Each DS0
          channel, originally a digitised voice-grade telephone signal,
          carries 8000 bytes per second (64,000 bits per second).  A DS1
          frame includes one byte from each of the 24 DS0 channels and
          adds one framing bit, making a total of 193 bits per frame
          at 8000 frames per second.  The result is 193*8000 = 1,544,000
          bits per second.
       
          In the original standard, the successive framing bits
          continuously repeated the 12-bit sequence 110111001000, and
          such a 12-frame unit is called a super-frame.  In voice
          telephony, errors are acceptable (early standards allowed as
          much as one frame in six to be missing entirely), so the least
          significant bit in two of the 24 streams was used for
          signaling between network equipments.  This is called
          robbed-bit signaling.
       
          To promote error-free transmission, an alternative called the
          extended super-frame (ESF) of 24 frames was developed.  In
          this standard, six of the 24 framing bits provide a six bit
          cyclic redundancy check (CRC-6), and six provide the actual
          framing.  The other 12 form a virtual circuit of 4000 bits per
          second for use by the transmission equipment, for call
          progress signals such as busy, idle and ringing.  DS1 signals
          using ESF equipment are nearly error-free, because the CRC
          detects errors and allows automatic re-routing of connections.
       
          Compare T-carrier systems.
       
          [Kenneth Sherman, "Data Communications : a user's guide",
          third edition (1990), Reston/Prentice-Hall/Simon & Schuster].
       
          (1996-03-30)
       
       

  DS1
       Digital Signal level 1 (ISDN, T1), "DS-1"
       
       

  DS1
     n.
     (''abbreviation'' for "digital signal 1.") ''See''
  '''T1'''.

  DS1
     n.
     (''abbreviation'' for "digital signal 1.") ''See''
  '''T1'''.

  DS1
     n.
     (''abbreviation'' for "digital signal 1.") ''See''
  '''T1'''.

  DS1
     n.
     (''abbreviation'' for "digital signal 1.") ''See''
  '''T1'''.

  DS1 /dˌiːˈɛs wˈɒn/
  specifikacija okvira naT1 kanalima