Download TR41.9.2-03-11-036-BillingProtection

Proposed change/modification
Document Number: TR-41.9.2-03-11-036
STANDARDS PROJECT:
TR41.9.2 - TSB31-C, Billing Protection – Sections updates
TITLE:
Proposal to revise TSB31-C, Billing Protection – Data Equipment Call
Durations, Loop Current Requirements and DID Answer Supervision
Signal Requirements test procedures
ISSUES ADDRESSED:
Update TSB31-C, Sections 12.1, 12.2, 12.4 and 12.6 of the TIA-968-A
measurement guidelines.
SOURCE:
Cisco Systems
CONTACTS:
Tim Lawler, Cisco Systems, e-mail: [email protected]
DATE:
November 11, 2003
DISTRIBUTION TO:
TIA TR-41.9.2 (TSB-31-C working group)
KEYWORDS:
TIA-968-A Billing Protection – test procedures.
NOTICE:
The contributor grants a free, irrevocable license to the Telecommunications Industry Association (TIA) to
incorporate text or other copyrightable material contained in this contribution and any modifications
thereof in the creation of a TIA Publication; to copyright and sell in TIA's name any TIA Publication even
though it may include all or portions of this contribution; and at TIA's sole discretion to permit others to
reproduce in whole or in part such contribution or the resulting TIA Publication. This contributor will also
be willing to grant licenses under such copyrights to third parties on reasonable, non-discriminatory terms
and conditions for purpose of practicing a TIA Publication which incorporates this contribution.
This document has been prepared by Cisco Systems to assist the TIA Engineering Committee. It is
proposed to the Committee as a basis for discussion and is not to be construed as a binding proposal on
Cisco Systems. Cisco Systems specifically reserves the right to amend or modify the material contained
herein and nothing herein shall be construed as conferring or offering licenses or rights with respect to
any intellectual property of Cisco Systems other than provided in the copyright statement above.
1
12
BILLING PROTECTION TIA-968-A, 4.8
12.1 Call Duration for Data Protective Circuitry TIA-968-A, 4.8.1.1
12.1.1 Background
This requirement applies to protective circuitry for data equipment that has access to
the public switched network. The two-second delay before transmission of the data
signal, after the off-hook condition is presented to the telephone network in response to
an incoming call, is to allow billing equipment to be connected and prepared for proper
billing. The specified -55 dBm limit for transmission is considered to be equivalent to no
transmission and applies in both the transmit and receive conditions.
12.1.2 Purpose
To verify that no data is delivered to or received from the network for the first two
seconds after answering an incoming call through a protective circuit.
12.1.3 Equipment
(1)
Applicable loop simulator SEL# 4.
(2)
Bandpass filter SEL# 12.
(3)
Digital sampling storage oscilloscope SEL# 24.
(4)
Frequency generator SEL# 27.
(5)
Ringing amplifier SEL# 33.
NOTE: Refer to Section 4.4 for equipment details.
2
12.1.4 Equipment States Subject to Test
Answering an incoming call (on-hook to off-hook transition).
12.1.5 Procedure
(1)
Connect the EUT to the test circuit of Figure 12.1-1.
(2)
Set the frequency generator for 1000 Hz and 0 dBm.
(3)
Set the oscilloscope to trigger on transition from the on-hook to the off-hook state of
the EUT.
(4)
Apply the ringing signal to the EUT.
(5)
Record the signal level that is transmitted to the network after the EUT goes offhook. Check for compliance during the first 2 s after going off-hook.
(6)
Connect the EUT to the test circuit of Figure 12.1-2.
(7)
Set the frequency generator to 1000 Hz and -55 dBm.
(8)
Place the EUT in the off-hook state. Measure the signal power that would be
delivered to the data equipment from the network through the EUT in response to a
received signal power of -55 dBm. Return the EUT to its on-hook state.
(9)
Increase the input signal 0 dBm.
(10)
Set the oscilloscope to trigger on transition from the on-hook to the off-hook state of
the EUT.
(11)
Apply the ringing signal to the EUT.
(12)
Measure the signal power that would be received by the data equipment from the
Network through the EUT (see comment (3)).
12.1.6 Alternate Methods
None suggested.
12.1.7 Suggested Test Data
(1)
Signal power in dBm for at least the first two seconds after transition to the off-hook
state in both directions of transmission.
(2)
Verification of data delay.
3
12.1.8 Comments
(1)
Actual data signals may be used in place of the signal generator.
(2)
Test frequencies other than 1000 Hz may be used.
(3)
The signal level measured in Step (12) should be no greater than the signal level in
Step (8).
NOTES:
(1) Select the appropriate loop simulator for the interface of the EUT.
(2)
Connect the bandpass filter across R1 of the loop simulator. Refer to the figures of
Section 68.3 of Part 68.
(3)
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of Section 68.3 of Part 68.
Figure 12.1-1. Call Duration, PC, Transmit
4
NOTES:
(1) Select the appropriate loop simulator for the interface of the EUT.
(2)
Connect the bandpass filter across R1 of the loop simulator. Refer to the figures of
Section 68.3 of Part 68.
(3)
Loop current is measured with a current meter in series with R2 of the loop simulator.
Refer to the figures of Section 68.3 of Part 68.
Figure 12.1-2. Call Duration, PC, Receive
5
12.2 Call Duration for Data Applications Approved Terminal Equipment TIA-968A, 4.8.1.2
12.2.1 Background
This requirement applies to data equipment that accesses the public switched network.
The two-second delay before transmission of the data signal after the off-hook condition
is presented to the telephone network in response to an incoming call is to allow billing
equipment to be connected and prepared for proper billing.
12.2.2 Purpose
To verify that the data equipment does not transmit or receive data for the first two
seconds after answering an incoming call.
12.2.3 Equipment
(1)
Applicable loop simulator SEL# 4.
(2)
Digital sampling storage oscilloscope SEL# 24.
(3)
Data generator SEL# 18.
(4)
Ringing amplifier SEL# 33.
NOTE: Refer to Section 4.4 for equipment details.
12.2.4 Equipment States Subject to Test
Answering an incoming call, transmitting and receiving data (on-hook to off -hook
transition).
12.2.5 Procedure
(1)
Connect the EUT to the test circuit of Figure 12.2-1.
(2)
Set the oscilloscope to trigger on the transition from the on-hook to the off-hook
state.
(3)
Apply the ringing signal to the EUT.
(4)
Monitor the signal transmitted by the EUT for at least two seconds after the on-hook
to off-hook transition under normal operating conditions. Verify that data
transmission is delayed for the required time. If a signal is observed in less than the
required time, verify that it is one of the allowed signals.
6
(5)
Connect the EUT to the test circuit of Figure 12.2-2.
(6)
Set the EUT to receive data.
(7)
Set the oscilloscope to trigger on the transition from the on-hook to the off-hook state
of the EUT.
(8)
Apply the ringing signal to the EUT.
(9)
Monitor the EUT to verify that it does not respond to the incoming data for the time
specified in the test requirement after going off-hook (see comment).
12.2.6 Alternative Methods
None suggested.
12.2.7 Suggested Test Data
Verification of the data delay.
12.2.8 Comments
It may not be possible to determine whether or not data has been received.
Engineering analysis and attestation by the applicant may be necessary in these cases.
7
NOTE: The companion terminal equipment should provide the termination for this test;
therefore, R1 of the loop simulator may be removed. The loop simulator
provides loop current for both the EUT and the companion equipment.
Figure 12.2-1. Call Duration, EUT, Transmit
8
NOTE: The companion terminal equipment should provide the termination for this test;
therefore, R1 of the loop simulator may be removed. The loop simulator
provides loop current for both the EUT and the companion equipment.
Figure 11.2-2. Call Duration, EUT, Receive
9
12.4 Loop Current Requirements TIA-968-A, 4.8.3
12.4.1 Background
The loop current restriction for the first five seconds, and subsequent requirements, are
necessary to ensure connection and operation of the billing equipment of the telephone
company.
12.4.2 Purpose
To measure the off-hook dc current drawn by the EUT from the loop simulator in the first
five seconds after the on-hook to off-hook transition.
12.4.3 Equipment
(1)
Applicable loop simulator SEL# 4.
(2)
DC current meter SEL# 19.
(3)
Digital sampling storage oscilloscope SEL# 24.
(4)
Frequency generator SEL# 27 (if required).
(5)
Ringing amplifier SEL# 33 (if required).
NOTE: Refer to Section 4.4 for equipment details.
12.4.4 Equipment States Subject to Test
The first five seconds after the EUT transfers from the on-hook to the off-hook state in
response to an incoming call.
10
12.4.5 Procedure
NOTE: Either of the two following methods can be used:
12.4.5.1
Method A: Comparison With Current through a 200-Ohm Resistor
(1)
Connect the EUT to the test circuit of Figure 12.4-1.
(2)
Set the dc voltage of the loop simulator to 42.5 V dc.
(3)
Set switch S1 to position "A”.
(4)
Adjust resistor R2 of the loop simulator to 1740 Ohms and record the loop current
through the 200 Ohm resistor.
(5)
Set switch S1 to position "B”.
(6)
Cause the EUT to go off-hook.
(7)
Monitor the dc current for the first five seconds after transferring from the on-hook to
the off-hook state. Record the minimum current level during the first five seconds.
(8)
If the dc current drawn by the EUT is equal to or greater than the dc current
measured in step (4), then the requirement is met.
12.4.5.2
Method B: Percent Change in dc Current
(1)
Connect the EUT to the test circuit of Figure 12.4-2.
(2)
Place the EUT in its off-hook condition and adjust resistance R2 to its maximum
value (1740 Ohms, 42.5 V dc).
(3)
Place the EUT in its on-hook state.
(4)
Set the oscilloscope to trigger on the transition from on-hook to off-hook of the EUT.
(5)
Cause the EUT to go off-hook.
(6)
Monitor voltage across the 10-ohm resistor for the first five seconds after transferring
the EUT from the on-hook state to the off-hook state. Record the maximum and
minimum voltage levels.
11
(7)
The percent change in current will be equal to the percent change in voltage of the
minimum voltage level relative to the maximum voltage during the first five seconds.
(8)
Set R2 set to its minimum value (400 Ohms, 56.5 V dc).
(9)
Repeat Step (3) through Step (7).
(10)
Set R2 to a value that produces a mid-range current (1200 Ohms, 56.5V).
(11)
Repeat Step (3) through Step (7).
12.4.6 Alternative Methods
None suggested.
12.4.7 Suggested Test Data
12.4.7.1
Method A: Comparison with 200 Ohm Resistor
(1)
Loop current measured with 200-ohm resistor (mA dc).
(2)
Loop current measured with EUT (mA dc).
(3)
Comparison of loop currents.
(4)
Resistor R2 range.
12.4.7.2
Method B: Percent Change in Loop Current
(1)
Maximum and minimum off-hook dc voltage during the first five seconds.
(2)
Percent change during first five seconds.
(3)
Resistor R2 range.
12.4.8 Comments
(1)
Chart recorder can be used in place of oscilloscope.
(2)
A dc current probe may be used with the oscilloscope to monitor current instead of
voltage.
12
NOTE:
(1)
Only the dc portion of the loop simulator circuit should be connected for this test.
(2)
Loop current is measured with a current meter in series with R2 of the loop
simulator. Refer to the figure 1.1 of Section 1 of TIA-968-A.
Figure 12.4-1. Loop Current, 200 ohm Method
13
NOTE: Only the dc portion of the loop simulator circuit should be connected for this test.
Figure 12.4-2. Loop Current, 25% Method
14
12.6 Operating Requirements for Direct Inward Dialing (Analog TE) TIA-968-A,
4.8.7
12.6.1 Background
This requirement ensures that the EUT for Direct Inward Dialing returns line reversed
answer supervision signal back to the network interface within 0.5 seconds of the called
PBX station answering the call. The requirement is necessary to initiate billing.
12.6.2 Purpose
To verify that the EUT for Direct Inward Dialing returns line reversed answer supervision
signal when the incoming call is answered by the called PBX station.
12.6.3 Test Equipment
(1)
Companion terminal equipment SEL# 15 (e.g. DTMF/rotary telephones,
communication test set, etc.).
(2)
Digital sampling storage oscilloscope SEL# 23.
(3)
Digital DC voltmeter SEL# 22.
12.6.4 Equipment states subject to test
Test the EUT to ensure the return of answer supervision to public switched telephone
network as soon as the called PBX station equipment answers the incoming call.
12.6.5 Test Procedure
(1)
Connect the companion terminal equipment and the digital DC voltmeter to the tip
and ring leads of the EUT as show in Figure 12.6-1.
(2)
Connect the digital DC voltmeter across the tip and ring leads of the EUT.
(3)
Connect the companion terminal equipment (e.g. a telephone) to the called station
under test.
(4)
Connect channel 1 of the storage oscilloscope (between ring lead and ground) to the
EUT.
(5)
Connect channel 2 of the storage oscilloscope (between ring lead and ground) to the
called station under test.
15
(6)
Originate a direct inward dialing call from the companion terminal equipment. The
line loop reversed answer supervision condition is to be applied within 0.5 seconds of
the time that:
(a)
The EUT permits the acceptance of further digits that may be used to route
the incoming call to another destination.
(b)
The EUT transmits signals towards the calling party, except for the call
progress tones, i.e., busy, reorder and audible ring, and the call is:
A.
Answered by the called, or another station;
B.
Answered by an attendant;
C.
Routed to a customer controlled or defined recorded announcement,
except for "number invalid," "not in service," or "not assigned;"
D.
Routed to a dialing prompt; or
E.
Routed back to the public switched telephone network or other
destination and the call is answered. If the status of the answered call
cannot be reliably determined by the EUT through means such as,
detection of answer supervision or voice energy, removal of audible
ring etc., the off-hook state is to be applied after an interval of not more
than 20 seconds from the time of such routing.
(7)
Monitor the EUT line loop polarity with the digital DC voltmeter.
(8)
Observe and record with the storage oscilloscope the elapsed period between the
time the called PBX station goes off-hook to answer the call and the time that the
EUT transmitted the line reversed answer supervision signal to the network.
(9)
Ensure that the line reversed answer supervision state maintains for the duration of
the call.
(10)
Repeat steps (6) through Step (9) for each call answering mode as required by TIA968-A, section 4.8.7 (i.e. answered by the attendant, answered by a recorded
message, forwarded call to another trunk, etc).
12.6.6 Alternative Methods
None suggested.
16
12.6.7 Suggested Test Data
State whether the EUT for Direct Inward Dialing complies with each of the conditions
specified in TIA-968-A, section 4.8.7.
12.6.8 Comments
This requirement applies only to EUT for connection to analog Direct Inward Dialing
access lines.
Figure 12.6-1. Operating Requirements for Direct Inward Dialing
17