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New Member

HELP! nm-8a/s Network module what speed?

I received network modules nm-8a/s with 8 serial interface for syncronous links. I was asked to use these interfaces on dedicated leased line (CDN) at 384 Kbit/s.

On cisco web site i found that these interfaces can work up to 128 Kbit/s is that true? So they should not support higher rates, isn't it?

What seems strange is that these interfaces seems to work fine with a clock needed for a link of 384 Kbit/s with the router acting as DTE while the DCE provided by the ISP (with a V.35 interface) generates the clock. They work but i don't know what is the real speed 128 (nominal limit for the interface) or 384 Kbit/s (stated by the ISP on the DCE).

The serial interfaces itself can generate a max clock of 128.000 (acting as DCE) while seems to accept a clock rate of 4.000.000 when working as DTE, is that normal?

Should i change nm-8a/s with nm-4T?

Why the nm-8a/s syncronous interfaces are so slow?

Thank You very much for Your help

New Member

Re: HELP! nm-8a/s Network module what speed?

Change to NM-4T.

I just did a check on one of our 26xx router with nm-8a/s and it does NOT support clockrates above 128k.

"The maximum speed is 115.2 kbps for async, 128 kbps for the sync external clock, and 125 kbps for the internal clock."

Hope this helps.



Re: HELP! nm-8a/s Network module what speed?

Ok this is the datasheet (max = 128 Kbps Syncronous mode) but the interface is working with a DCE generating a clock much higher of 128.000, this is what i can't understand...

It seems like the clock and andwidth supported are not directly related. This can be true on frame relay link (CIR and Burst Rate) an on channelize PRI but on a leased line it should not be possible!

Where am i mistaking?

Thank You