invert data command

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Mar 26th, 2008
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can please someone explain what does

the invert data command is for and it's purpose.

What7s the difference if you have it configured and when you don't.we7re using a serial interface

I'm suspecting that the local vendor forgot to input the (non invert) command

at the NTu when they replaced which caused the interface not to go up.

I appreciate your assistance

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paolo bevilacqua Wed, 03/26/2008 - 02:24
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The command is rarely used, needed only when certain abnormal electrical conditions exists with the connected device. NTUs do not have an equivalent command.

Giuseppe Larosa Wed, 03/26/2008 - 02:36
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this command can play an important role for synchronus serial lines with speed > 64 kbps.

If the CSU/DSU does not support SCTE (serial clock transmit external) the invert command allows to compensate for phase shifts between the data and clock signals.

SCTE is the clock echoed back from the data terminal equipment (DTE) device (for example, a router) to the data communications equipment (DCE) device (for example, the CSU/DSU).

the difference is the introduction or not of a phase shift on the data signal.

So if this applies I would suggest you to try the command to see if it fixes your problem.


Use this command if the DCE cannot receive SCTE from the DTE, the data is running at high speeds, and the transmission line is long. The dte-invert-txc command prevents phase shifting of the data with respect to the clock.

On the Cisco 4000 series, you can specify the serial Network Processor Module timing signal configuration. When the board is operating as a DTE, the dte-invert-txc command inverts the TXC clock signal it gets from the DCE that the DTE uses to transmit data.

If the DCE accepts SCTE from the DTE, use no dte-invert-txc.

If you want to find more info try to search "troubleshooting serial lines" on CCO.

hope to help

best regards



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