User manual

Configuring and Monitoring Through the LCD
4-10 Campus-RS Fractional Interface Card User Manual
INVERTING THE TRANSMIT CLOCK
There may be circumstances in which it is either desirable or necessary to
invert one or more of the TT, SCT, and SCR clocks. This could be true if the
host equipment provides inverted clock signals, if the differential clock
signals are switched in the data cable, or if there is excessive clock delay. The
Fractional Interface Card allows you to invert any of these clock signals by
changing the appropriate Invert Clock option.
For physical-layer protocols which have unbalanced (single-ended) clock
signals, the Invert Clock option has the effect of simply inverting the clock
signal. This appears as a 180° phase delay. For physical-layer protocols
which have balanced (two-wire) clock signals, the Invert Clock option has the
effect of switching the inverting and non-inverting contacts.
There are two settings for each Invert Clock option:
• OFF leaves the output clock in its normal, non-inverted, state.
• ON inverts the clock signal or, for the TT input, inverts the input signal
internally.
To invert a transmit clock:
1 Press Escape until CAMPUS RS I/F: FRAC displays.
2 Press Next until DATA PORT CONFIG & STATUS displays, then press
Enter. RATE MULTIPLIER displays.
3 Press Next until the appropriate invert clock option displays:
• INVERT INPUT CK to invert the TT signal
• INVERT OUTPUT TX CK to invert the SCT clock
• INVERT OUTPUT RX CK to invert the SCR clock
If you change the Rate Multiplier, the Data Port Rate changes
automatically to reflect the new multiplier.