VeEX MTT-14B User Manual page 50

MTT-14B e_Manual D07-00-083P RevA00
1-15, and time slots 17-31 correspond to channels 16-30. In
PCM-30, time slot 16 is used for the multiframe alignment sig-
nal. Fractional E1 is not offered with unframed signals, because
framing is required to determine the location of time slots.
The time slots specified for transmit and receive need not be
the same. The test set will assume that all incoming data is
received byte by byte in ascending channel order.
2. When finished, press ENTER to validate the settings and return
to TEST CONFIGURATION.
RX PORT
Options: TERM (F1), BRIDGE (F2), MONITOR (F3)
Configures the 2.048 Mbit/s receiver.
These settings let the test set electrically decode a 2.048 Mbit/s
signal under a wide range of resistive cable losses. They also
determine which electrical load will be placed on the circuit by
the test set. These settings have no effect on the transmitters.
On a 2.048 Mbit/s circuit, there must always be exactly one
receiver that applies the low impedance (75/120Ω) termination.
There should never be two or more receivers applying a low
impedance termination.
CAUTION! If uncertain, select BRIDGE, this will protect the 2.048
Mbit/s signal.
• TERM: Terminate the received signal with a 75 or 120Ω im-
pedance termination. The tested signal has been transmitted
over real cable at a level between approximately +6 and -43
dB. Using TERM mode will disrupt the circuit.
• BRIDGE: Applies high-impedance isolation resistors to the
circuit. This isolation circuit will protect the signal from any
possible disruption. The tested signal has been transmitted
over regular cable at a level of approximately +6 and -43 dB.
• MONITOR: Used when a measurement is made at a protected
monitoring point, at a level between -15 and -30 dB.
If a 0 dB signal is received, the BPV/CODE LED will be red.
This happens when the test set is plugged into an OUT jack.
In this case, select TERM. If uncertain if a jack is bridged or
protected, try BRIDGE first.
TX CLOCK
Options: Rx (F1), INTERN (F2)
• Rx: The test set uses the timing from the received signal as
the clock source.
• INTERN: Use the internal timing of the test set. This timing is
not synchronized to the network. Use when loopback testing
where synchronization is not required.
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