Analog Line problems

See Avaya Tech Tip 59 (Pasted below):
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Analog Trunk Standards
It has come to the attention of Avaya that in certain cases, IP Office systems have been
installed into locations where the Analog trunks provided have not met the TIA
(Telecommunications Industry Association) requirements for the United States.
All IP Office systems are engineered and rigorously tested to ensure that they meet the
relevant local approvals standards.
If an IP Office is connected to trunks that fall outside of these standards, a number of
issues may occur, the symptoms of which may include the IP Office being unable to
seize a line, tones not being recognized, and noise on the line.
This can particularly cause issues where a previous system is replaced with an Avaya IP
Office, as the IP Office has tighter tolerances than Magix, Partner and various other
switches, and may not function correctly with poor quality trunks that have been used
æsatisfactorilyÆ with the previous system. The customer may have noticed a hum or
other noise on their lines previously, but as the trunks appeared to work, this may have
accepted this as standard behaviour, despite being an indicator of poor trunk quality.
Explaining this to a customer can obviously prove difficult, as the earlier system
appeared to work correctly, and can cause concern about the quality and reliably of the
newer system.
As a result, Avaya would like to state that we can only guarantee compatibility with
Analog trunks that meet the required standards.
The objective for all trunks should be an NMSa Reading (dBrnc) of less than 20 dBrnc,
with a gain of -3.5 db within +/- 1dB.
Loop, or trunk noise of 21-30 dBrnc is marginal as 30 dBrnc is approached and requires
investigation and possible intervention by the service provider.
Noise above 30 dBrnc is unacceptable, and will almost certainly lead to issues like those
mentioned above û the service provider will need to investigate these trunks, and
provide a remedy.
It is recommended that for all new installations, or where the IP Office is replacing an
existing system, the customer should be advised to ask their service provider to check
the line noise and gain levels on their Analog trunks in order to confirm that the lines are
within the requirements.
Issued by:
Avaya SMBS Tier 4 Support
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