Technical data

Chapter 18 489
T1 Analyzer
Making T1 Measurements
T1 Analyzer
• Line Code: Configures the test set to transmit and expect to receive a line code
that is compatible with the network’s design. There are two types of line coding
used in T1 networks:
— AMI - Alternate Mark Inversion is a traditional line code.
— B8ZS - Bipolar 8 Zero Substitution replaces runs of 8 zeroes with a special
code that is not compatible with AMI. It allows greater flexibility of data
patterns by enhancing repeater synchronization by increasing pulse density,
thereby providing greater throughput.
• Framing: Configures the test set to transmit and expect to receive a particular
framing pattern that is compatible with the network’s design. It enables the test
set to receive the T1 signal and to then synchronize, identify, and extract the
individual channels.
— Unframed - The 193rd (framing) bit is set to 0 or 1, depending on the
pattern.
— D3/D4 - A 12 frame structure accomplished by sending a unique pattern on
the 193rd (framing) bit.
— ESF - A 24 frame structure accomplished by sending a unique pattern on the
193rd (framing) bit. In this mode the frame bits are used to transmit a CRC
and carry information to accommodate alarms and control
• Pattern: Configures the test set to expect a particular test pattern. Many test
patterns are available to 'stress' the circuit in a particular manner or to gain
maximum insight into a particular problem.
• Tx Pattern: Allows you to select either Normal or Inverted patterns.
• Tx Clock: Configures the test set to use one of the following methods to derive
the transmit clock frequency:
— Internal - The transmit clock is derived within the test set and is
independent of the incoming signal. This is useful when the device or line
under test is configured to synchronize on the incoming signal. In this case
the return clock frequency of the return signal should match the transmit
clock frequency of the test set.
— Primary Rx - The transmit clock frequency is derived from the signal
received at the Primary Rx jack on the test set.
— Secondary Rx - The transmit clock frequency is derived from the signal
received at the Secondary Rx jack on the test set.
• Channel: Applicable only in the Channel BERT mode. Sets the active channel