Download TR41.3.5-13-08-017-LR1-ANSI-TIA-PN-470 210

Telecommunications Industry Association
TR41.3.5-13-08-017-LR1
Document Cover Sheet
Project Number
ANSI/TIA-PN-470.210-E
Document Title
Late Ballot Comments
Source
Microsemi Semiconductor Inc.
Contact
Name: Michel Darveau
Complete Address: 400 March Rd.
Ottawa, Ontario, Canada, K2K 3H4
Distribution
TR-41.3.5
Intended Purpose
of Document
(Select one)
X
Phone: 1-613-270-7048
Fax:
Email: [email protected]
For Incorporation Into TIA Publication
For Information
Other (describe) -
The document to which this cover statement is attached is submitted to a Formulating Group or subelement thereof of the Telecommunications Industry Association (TIA) in accordance with the
provisions of Sections 6.4.1–6.4.6 inclusive of the TIA Engineering Manual dated October 2009, all of
which provisions are hereby incorporated by reference.
Abstract
Please see attached comments on ANSI/TIA-PN-470.210-E ballot document.
Identification of comments as editorial or technical, proposed resolution of editorial comments, and some
discussion of technical comments have been added by the editor in the –LR1 version. The proposed
editorial comment resolution and discussion of technical comments are to referred to TR-41.3.5 for
consideration at its August 2013 meeting.
v1.0 – 20050426
Telecommunications Industry Association
TR41.3.5-13-08-017-LR1
The following comments are submitted for review by the developers of TIA-PN-470.210-E.
Page 3, 3.2 Definitions
The Echo Return Loss definition is not the same as the IEEE 743-1995 standard commonly used. This
should be mentioned in a note to avoid any confusion.
Comment is Editorial
Resolution: IEEE 743-1995 has been withdrawn. The 1/f weighting characteristic has been in the
document since ANSI/TIA-470.210-C was published in 2004. It is based on ITU-T
Recommendation G.122. See contribution TR41.3.5-00-02-008 for further information.
However, a note will be added following the ERL equation in 5.5.1.2 pointing out the
difference. The relevant documents will also be added to the list of informative
references.
Page 4, 4.1.3 Test Equipment Performance:
It is written that the source impedance shall be lower than 900 Ohms, and should be lower than 600
Ohms. This is not accurate. The source impedance needs to be 900-Ohm for some tests and 600-Ohm for
others. The instrument needs to comply with these numbers as appropriate. Of course an instrument with
a lower source impedance can also be used if the impedance is built up with external resistances but the
transmit level from the instrument has to be adjusted.
Comment is Technical
Resolution: I do not believe a matched impedance source is necessary for the type of measurements
being made, but this can be discussed in the TR-41.3.5 meeting.
Page 4, 4.2 DC Feed Circuit
The second bullet is a specification for the AC signal source, not for the DC feed circuit.
Comment is Editorial
Resolution: Agreed. The 900 ohm termination impedance is not part of the dc feed circuit and is not
shown in Figure 1. Bullet item should be deleted.
The third bullet is a specification for the combined AC signal source and DC feed circuit, or for the DC
feed circuit with the AC port terminated into a 900-Ohm resistor. This should be written down correctly.
Comment is Editorial
Resolution: Agreed. The dc feed circuit should be well enough balanced that 30 dB of return loss
relative to 900 ohms is seen at the CPE terminals when a 900 ohm termination is placed
across the “source or termination” terminals. Text will be modified to indicate this.
Page 5, Figure 1
The arrows to the left of the two capacitors should be labeled “From AC source or to AC termination”
Comment is Editorial
Page 2
Telecommunications Industry Association
TR41.3.5-13-08-017-LR1
Resolution: Propose not to change unless deemed critical. Do not have editable drawing of figure,
so it would have to be re-drawn.
Page 7, 5.3.1.1 Requirements
The on-hook resistance numbers between 0 and 100 Volts are excessively high. The 25 M and 15 M
numbers at 100 V translate into 4 uA and 6.7 uA of leakage current. The current doesn’t need to be that
low for the network to operate correctly and many phones which are currently in use violate these limits.
Those are phones with LCD display or with memory and that are line powered. Meeting these
requirements requires the use of batteries, but it is common practice for subscribers to not put them in.
These numbers should be rationalized with phones that are deployed and working perfectly well. This
point should be addressed by the phone manufacturers.
Comment is Technical
Resolution: No Change. This would be a technical change and would have to be agreed to by ATIS
(Alliance for Telecommunications Industry Solutions) as well since it is based on the
requirement in ATIS—600401.2006 (formerly ANSI/T1.401-2000) for the customer
installation (i.e., all of the CPE connected to the network interface) to provide a
minimum of 5 Mohms resistance when everything is on hook.
Pages 9 and 10, 5.3.2.2 Method of Measurement
The DC feed circuit doesn’t include an adjustable voltage source and neither any adjustable resistors. So,
how is the current going to be adjusted to obtain the values listed in Table 2? The DC feed circuit should
be changed to show an adjustable voltage source instead of the fixed 50 Volts and the enumerated item 2
needs to mention adjusting the dc feed voltage to obtain the desired current.
Comment is Technical
Resolution: Valid point, but a technical issue. Is the dc feed circuit of Figure 1 really needed here
(Figure 6), or would a simplified battery and variable resistance supply such as is shown
in Figure 7 be sufficient?
Page 10, 5.3.3.2 Method of Measurement
The second enumerated item should be changed to say: “Place the CPE off-hook and adjust the variable
resistor R to obtain 20 mA of loop current.
Comment is Editorial
Resolution: Accepted with slight modification as shown above.
Page 12, On-Hook Impedance
The B-type ringers are obsolete and a note has even been included to state it. So, why base the
requirements on B-type ringers? The requirements should be written for A-type ringers.
Comment is Technical
Resolution: No Change. This would be a technical change and would require elimination of B-type
ringing from the “Part 68” requirements in ANSI/TIA-968-B. A quick check of the
ACTA database indicates that virtually every applicable product approved in 2012 was
Page 3
Telecommunications Industry Association
TR41.3.5-13-08-017-LR1
identified as having a B-type ringer. It is perhaps worth noting that ATIS—
600401.2006 (formerly ANSI/T1.401-2000) has changed to specifying only 20 Hz
ringing.
Page 13, 5.4.1.2 Method of Measurement
The second enumerated item mentions measuring the ac voltage but it is not specified anywhere what to
do with this result. Is the intent to adjust the source voltage to obtain the Table 3 levels on the meter? This
would compensate for the source impedance of the AC signal generator although no such impedance is
shown in Figure 9.
Comment is Editorial
Resolution: Comment accepted. Text for step 2 modified to indicate voltmeter is used for adjusting
the level of the ac signal source.
Pages 13 and 14, 5.4.2.1 Requirement
Again, why use B-type ringers? This should be based on A-type.
Comment is Technicaal
Resolution: This is a technical issue, but I would propose no change for reason noted previously.
Pages 19 and 20, 5.5.1.2 Method of Measurement
The enumerated items 8 and 9 specify to repeat steps 3 to 6 with an increased DC feed resistance. Does
this mean that the Echo Return Loss calculation of step 7 is not to be performed and the only requirement
applicable to these lower current settings is the single frequency specification from Figure 15? Or is it that
steps 8 and 9 should state to repeat steps 3 to 7? As written it is not clear whether the Echo Return Loss
specification applies at lower current levels.
Comment is Technical
Resolution: It seems strange to only check ERL at the maximum current condition. However, I
checked all the way back to ANSI/TIA-470.210-C and found the same issue. I then
checked ANSI/TIA-470-B. It seems to require measuring ERL only at 70 mA of current
(or the max current the set can draw), while requiring the single frequency return loss
measurements to be made at both 70 mA and the minimum current available from the
battery feed circuit, but not less than 20 mA.
Page 4