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Cisco uBR7200 Series Universal Broadband Routers

Field Notice: *Expired* FN - 12870 - New Calibration Technique to Increase RF Robustness on uBR Line Cards


Revised November 22, 2006

September 26, 2000

NOTICE:

THIS FIELD NOTICE HAS BEEN ARCHIVED AND IS NO LONGER MAINTAINED OR UPDATED BY CISCO.

THIS FIELD NOTICE IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE, WARRANTY OR SUPPORT. USE OF THE INFORMATION ON THIS FIELD NOTICE OR MATERIALS LINKED FROM THIS FIELD NOTICE IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS FIELD NOTICE AT ANY TIME.


Products Affected

Product

Comments

UBR-MC16C

uBR7200 Modem Card, 1 downstream, 6 upstream, option

Problem Description

Cisco continues to improve RF robustness for uBR cable line cards. These improvements require a combination of a new calibration technique on the line cards performed by manufacturing, and an upgrade of the uBR software to an IOS version which incorporates DDTS CSCdr90141. The new calibration technique was put in production on the UBR-MC16C on July 8, 2000.

This new technique could cause some cable modems in the field to operate with a +3 dB offset on the upstream transmit if installed on uBRs with an IOS version that does not incorporate CSCdr90141.

This new technique could cause inconsistencies in a lab environment when using a spectrum analyzer to measure upstream power level at the input of the linecard. The SA would indicate a +3 dBmV signal instead of 0 dBmV when using the CLI command:

cable ux power-level 0

The field problem could possible occur ONLY IF the newly calibrated board from manufacturing is running a software IOS version without CSCdr90141.

Background

The improvements in calibration for cable modem line cards are meant to increase the RF robustness of the line cards.

Problem Symptoms

The problem could be exhibited in the field as cable modems with a power output 3 dB too high.

Workaround/Solution

If you have a UBR line card which has been burst mode calibrated, you should use an IOS version with the fix for DDTS CSCdr90141.

DDTS

To follow the bug ID link below and see detailed bug information, you must be a registered user and you must be logged in.

DDTS

Description

CSCdr90141

Add 3db power adjustment to burst mode calibrated cable line card

How To Identify Hardware Levels

You can find if a UBR line card has been burst mode calibrated by examining the hex output of the IOS show diag command.

Example of a UBR-MC-16C that has not been burst mode calibrated:

Part Number : 800-05266-01
Board Revision : E0
CLEI Code : CNL1SU0DAA
Deviation Number : 0-0
Fab Version : 01
PCB Serial Number : CAB0330367P
RMA Test History : 00
RMA Number : 0-0-0-0
RMA History : 00
Calibration Data : Minimum: -10 dBmV, Maximum: 25 dBmV

Calibration values : 0x9DA0 0x9C20 0x9C10 0x98C0 0x98B0 0x9DC0
0x9C20 0x9C20 0x98C0 0x98D0 0x9D70 0x9BB0
0x9BA0 0x9840 0x9840 0x9DA0 0x9BF0 0x9BC0
0x9850 0x9840 0x9E30 0x9CA0 0x9C80 0x9960
0x9940 0x9DE0 0x9C10 0x9C10 0x9890 0x9890

EEPROM format version 4
EEPROM contents (hex):
0x00: 04 FF 40 00 F8 41 01 00 C0 46 03 20 00 14 92 01
0x10: 42 45 30 C6 8A 43 4E 4C 31 53 55 30 44 41 41 80
0x20: 00 00 00 00 02 01 C1 8B 43 41 42 30 33 33 30 33
0x30: 36 37 50 03 00 81 00 00 00 00 04 00 C8 3F F6 19
0x40: 1E 9D A0 9C 20 9C 10 98 C0 98 B0 9D C0 9C 20 9C
0x50: 20 98 C0 98 D0 9D 70 9B B0 9B A0 98 40 98 40 9D
0x60: A0 9B F0 9B C0 98 50 98 40 9E 30 9C A0 9C 80 99
0x70: 60 99 40 9D E0 9C 10 9C 10 98 90 98 90 FF FF FF

"FF FF FF" indicates that there is no calibration data. A UBR-MC16C which has been burst mode calibrated will show "0C 00 FF" in these three bytes.

For More Information

If you require further assistance, or if you have any further questions regarding this field notice, please contact the Cisco Systems Technical Assistance Center (TAC) by one of the following methods:

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