| The LBT is a Bit Error
Rate Tester for testing synchronous or asynchronous
modems and other DCEs. Testing can be conducted over
full duplex or half duplex links. The LBT can also test
modems connected in multipoint configuration for polling
operation. A network with up to 32 slave modems is
supported.
The LBT operates
synchronously or synchronously at data rates from 75 bps
to 38.4 kbps. When operating in synchronous mode, five
test patterns are available: 511 or 2047 pseudo random,
7 space 1 mark, 7 mark 1 space, or alternating
mark/space. In asynchronous and multipoint modes, only
the 511 bit pattern is available.
When testing a DCE, a
loop is performed, sending the data back to the LBT. The
LBT compares the received data with the transmitted
pattern and presents the result on an LCD display,
counting bit errors, block errors and error-seconds. The
LBT also features an INJECT ERROR push button which
enables the user to check the tester and the line by
introducing errors in the transmitted data stream.
Block sizes can be set to
512 bits, 1000 bits, 1024 bits, 2048 bits and 10 kbits.
When testing multipoint, a block size of 512 bits is
used.
The LBT can generate its
own clock or receive clock from the connected DCE.
Set-up and operation are
initiated from the front panel using soft keys and an
interactive menu selection on an LCD message display.
Ten indicator LEDs display the activity of the interface
signals.
The LBT comes in a
convenient hand-held case. The unit is powered by a
detachable external power supply unit.
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