Mr Rettinger for your information,I have retrieved the info on the ISDN receiver sensitivity test in the TREG data base, 1994 message best regards Pierre-Marie *********************************************************************** From: Pete Van Raalte List-Post: [email protected] Date: Thu, Oct 13, 1994 4:35 PM
John may be able to apply the method we use for ISDN Primary rate. John asked about the receiver sensitivity test in BABT 340, Table 3, test 17. We do test 18, which is the equivalent for PRI, and we definitely have a K-Mart equivalent to the expensive setup suggested by BABT. (Pardon the commercial reference.) We loop back through a 6 dB attenuator, and run a test program that assures we get back what we sent out. The software tests all 24 channels for about 10 seconds. One bad bit constitutes a failure. While this test has not been formally presented to BABT, our UK consultant feels that it is defensable as a reasonable substitute. I would appreciate hearing from anyone with opinions on the acceptability of this procedure. From: Nick Evans List-Post: [email protected] Date: Fri, Oct 14, 1994 2:31 PM >From the work we've been involved with in this area I can confirm previous comments that the ISDN receiver sensitivity test for BABT PQAA certification can be much simplified from the type approval requirements specified in the ETSs. For the test BABT has suggested to us a link with 6dB attenuation to simulate a maximum line length, there is no need to introduce further impairments such as noise or jitter. We have also been instructed that the test must evaluate receiver performance at layer 1, ie with no higher level error correction distorting the results. One way we have looked at doing this is to set up a low level loopback on the Equipment under test (as specified in I.430 I am told). A pattern can then be fed into the receive path and measured on transmit path. There are reasonably priced bits of equipment around which can do this (although I am not sure the price falls into the K-MART league). I know other companies have also looked at assigning one sample of their actual product with slightly modified software to act as the reference Pattern Generator and bit error rate detector. Their proposal in this case would be that this modified equipment becomes a QA reference sample. We get involved with QA samples a lot when it comes to testing things like Call Routing Apparatus (CRA) so I don't see why any reasonable proposal in this respect would not be accepted by BABT. From: Dave Clement List-Post: [email protected] Date: Tue, Oct 18, 1994 8:48 AM We do are doing test 18 the same way and it has been accepted by BABT via approval of our "Quality Plan". As a matter of fact most of the tests in Table 3 are not conducive to a production line when compared against the standard refernces. We use the "Quality Plan" as the vehicle by which we describe how we are going to meet all the supplemental requirements in part 2 of 340 and have submitted it to BABT for approval. Any revisions are submitted for approval in the same way a product design change is. This approach effectively eliminates the need to "defend" our methods at audit time. Revised: May 24, 1995
