Patton electronic 2720/I Series user manual DS0 Line Rate 64kbps default Options 64kbps, 56kbps

B8ZS: Bipolar violations occur when consecutive pulses are of the same polarity. In B8ZS, or Bipolar Eight Zero Substitution, bipolar violations are introduced deliberately to indicate that eight zeros have been transmitted. This special encoding is recognized by the receiver and decoded correctly. See AT&T TR62411 Section 4.2.2 for a detailed description of B8ZS. This enables information to be sent over a T1 connection without any constraints on the data’s pulse density. This is the most acceptable way to accomplish 64 kb/s on each DS0 channel.

B7ZS: This stands for Bipolar Seven Zero Substitution. Instead of introducing bipolar violations, this method substitutes a one for a zero in bit 7 (out of 8) of a DS0 channel when the data in that channel are all zeros. This is a special form of AMI and is compatible only with special equipment. For most applica- tions, AMI or B8ZS will suffice.

cDS0 Line Rate: 64kbps (default)

Options: 64kbps, 56kbps

64kbps: Also known as Clear Channel, this takes full advantage of the available bandwidth in a DS0 channel. Implementing it usually requires B8ZS line coding. In certain cases, special equipment may implement Clear Channel using AMI or B7ZS. Consult the equipment manual for compatibility. Your carrier will advise you on whether to use 64 or 56 kb/s. Campus applications may not have such restrictions, enabling you to use 64kbps. In Unframed format, the 24 DS0s and the fram- ing bits are combined to provide 1.544Mb/s for your use.

56kbps: This uses only the first seven bits of the DS0, limiting the data rate per DS0 channel to 56 kb/s. Your carrier will advise you on whether to use 64 or 56 kb/s. This is not available when using the Unframed format.

dClocking: Network (default)

Options: Network, Internal, External

Network: This is the most commonly used setting when connect ing to a carrier’s network. In this mode, the unit recovers the clock from the received signal and uses it to transmit data. In this way the unit remains synchronized to a master clock. In campus applications, one of the units must be set to Internal clock, and the other end is set to Network clock. At all times, there must be only one clock source. Otherwise, clock slips and framing errors and bit errors may occur.

Internal: This is commonly used in campus applications, where the unit is not connected to the public telephone network directly. In this mode, the unit uses the on-board oscillator as the transmit clock source.

External: This is a special mode that should only be used with the Unframed format. In this mode, the unit requires a 1.544 Mhz clock signal from the DTE via the external clock pin on the DTE interface connector. Most applications will use Network or Internal clock modes.

eLine Build Out (dB): 0 – 133 feet, 0 dB (default)

Options: 0 – 133 feet, 0 dB 133 – 266 feet 266 – 399 feet 399 – 533 feet 533 - 655 feet -7.5 dB

-15.0 dB -22.5 dB

This controls the transmitter signal strength and pulse shape. For most applications, the default setting will suffice. When connecting to a carrier connection, the carrier will determine what LBO is necessary. 0 dB provides the highest signal strength and therefore the longest dis- tance, while –15.0 dB provides the lowest usable signal strength. The last setting, –22.5 dB, is usually only used to test the line and should not be used in normal applications.

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