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3.123 bytes |
Service Hints & Tips |
Document ID: VLAR-3E7MBH |
External 28.8 (V.34)/14.4kbps Commercial Data/Fax Modem 7852-013 - Unable to remove the Carrier Detect
Applicable to: World-Wide
Problem:
Customer wants to take off the Carrier Detect. Can the Carrier Detect be taken off?
Solution:
No. The modem is operating per the ITU-T V.25bis specification. In V.25bis paragraph 4.1.1.7, it states that circult 109 (RLSD, aka CD), should follow the state of circuit 106 (RFS, aka CTS).
Additional Information:
There has been some confusion among modem manufacturers on this point, and some modem manufacturers follow the recommendation, while others, don't follow the recommendation.
Most hardware manufacturers know that this has been a problem with synchronous modems in the past and have chosen to ignore the CD signal. The V.25bis specification calls for 107 (DSR) to be used to indicate that a connection has been established and NOT CD.
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Hint Category |
Modems, Performance | |
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Date Created |
11-02-97 | |
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Last Updated |
19-11-98 | |
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Revision Date |
19-11-99 | |
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Brand |
IBM Options | |
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Product Family |
Modems | |
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Machine Type |
28.8K | |
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Model |
7852013 | |
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TypeModel |
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Reverse Doclinks |
Frank Hayes - CMVC case 1751 |