CS-03 Part I — Requirements for Terminal Equipment (TE) and Related Access Arrangements Intended for Direct Connection to Analog Wireline Facilities (sf09835)

2. Electrical and Mechanical Stresses

2.1 Mechanical Shock

2.1.1 Requirements

Unpackaged terminal equipment (TE) and network protection devices shall comply with all the requirements specified in sections 2 and 3 both prior to and following the application of all of the mechanical stresses outlined in this section, notwithstanding that some of these stresses may result in partial or total destruction of the equipment.

  1. Hand-held items normally used at head height: 18 random drops from a height of 1.5 m onto concrete covered with 3 mm asphalt tile or similar surface.
  2. Tabletop (desktop) equipment 0–5 kilograms: six random drops from a height of 750 mm onto concrete covered with 3 mm asphalt tile or a similar surface.

2.1.2 Method of Measurement

  1. TE and protective circuitry equipment unpackaged:
    1. Hand-held items normally used at head height: 18 random drops from a height of 1.5 m onto concrete covered with 3 mm asphalt tile or similar surface.
    2. Tabletop (desktop) top equipment (0–5 kg): these tests are performed onto concrete covered with 3 mm asphalt tile or a similar surface; one 750 mm face drop on each normal or designated rest face; one 750 mm drop on all other faces; and one 750 mm corner drop on each corner.
  2. The drop tests specified in the mechanical shock conditioning stresses shall be performed as follows:

     

    Face Drop
    The unit shall be dropped such that the face which is to be struck is approximately parallel to the impact surface.

    Corner Drop
    The unit shall be dropped such that, upon impact, a line from the struck corner to the centre of gravity of the packaged equipment is approximately perpendicular to the impact surface.

    Edgewise Drop
    The unit shall be positioned on a flat test surface. One edge of the rest face shall be supported with a block so that the rest face makes an angle of 20 degrees with the horizontal. The opposite edge shall be lifted to the designated height above the test surface and dropped.

    Cornerwise Drop
    The unit shall be positioned on a flat test surface. One corner of the rest face shall be supported with a block so that the rest face makes an angle of 20 degrees with the horizontal surface. The opposite corner should be lifted to the designated height above the test surface and dropped.

    Random Drop
    The unit shall be positioned prior to release to ensure as much as possible that, for every six drops, there is one impact on each of the six major surfaces and that the surface which is to be struck is approximately parallel to the impact surface.

2.2 Dielectric Strength

2.2.1 Requirements

TE shall have a voltage applied to the following combination of points listed in Table 2.2.1. The test voltage shall be 50–60 Hz AC:

  1. all telephone connections;
  2. all power connections;
  3. all possible combinations of exposed conductive exterior surfaces of such equipment or circuitry, including grounding connection points but excluding terminals for connection to other TE;
  4. all terminals for connection to registered protective circuitry or non-registered equipment;
  5. all auxiliary lead terminals;
  6. all E&M lead terminals; and
  7. all PR, PC, CY1 and CY2 leads.

Gradually increase the voltage from zero to the values listed in Table 2.2.1 over a 30-second time period and maintain the voltage for one minute. The current through the points shall not exceed 10 mA peak at any given time during this 90-second interval.

Equipment states necessary for compliance with the requirements of this section that cannot be achieved through normal means of power shall be achieved artificially by appropriate means.

Table 2.2.1 — Voltage Applied for Various Combinations of Electrical Connections
Voltage source connected between:Vac r.m.s. *
(1) and (2)1500
(1) and (3) (see notes 1 and 2)1000
(1) and (4) (see note 2)1000
(1) and (5) (see note 2)1000
(1) and (5)(see note 2)1000
(1) and (6) (see note 2)1000
(2) and (3) (see note 1)1500
(2) and (4)1500
(2) and (5)1500
(2) and (6)1500
(2) and (7)1500
(3) and (5) (see notes 1 and 2)1000
(3) and (6) (see notes 1 and 2)1000
(4) and (5) (see note 2)1000
(4) and (6) (see note 2)1000
(5) and (6) (see note 2)1000

Notes:

Vac r.m.s. = Value to which test voltage is gradually increased

  1. A telephone connection, auxiliary lead, or E&M lead that has an intentional DC conducting path to earth ground at operational voltages (such as a ground-start lead), may be excluded from this requirement in that operational state. Leads excluded for this reason shall comply with the requirements of Section 2.3.10.1.
    • A telephone connection, power lead, auxiliary lead or E&M lead that has an intentional DC conducting path to earth ground for protection at the leakage current test voltage (such as through a surge suppressor) may have the component providing the conducting path removed from the equipment for the leakage current test in that operational state. Components removed for this reason shall comply with the requirements of Section 2.3.10.2.
  2. For multi-unit equipment interconnected by cables that is evaluated and registered as an interconnected combination or assembly, the specified 10 mA peak maximum leakage current limitation, other than between power connection points and other points, may be increased, as described here, to accommodate cable capacitance. The leakage current limitation may be increased to (10N + 0.13L) mA peak, where L is the length of the interconnecting cable in the leakage path in metres and N is the number of equipment units that the combination or assembly will place in parallel across a telephone connection.
  3. Radio frequency (RF) filters and surge protectors on the line side of power supplies may be disconnected before making dielectric strength measurements. As an alternative to disconnecting these filters and surge protectors, this measurement may be made using a DC voltage equal to the peak AC test voltage.

2.2.2 Method of Measurement

Be advised:

Adequate safety precautions should be observed.

  1. Connect the TE to the test circuit of Figure 2.2.2.
  2. Select the appropriate TE test points and connect to the output of the test setup.
  3. Place the TE in the first test state.
  4. Over a 30-second interval, the test voltage level shall be gradually increased from zero to the level required for the connections being tested. The maximum voltage level shall be maintained for an additional 60 seconds.
  5. Monitor the resulting current and the applied voltage level for the 90-second test period.
  6. Record the maximum current measured during this period.
  7. Adjust the source for zero-volt output.
  8. Repeat steps (4) to (7) for all applicable operational states.
  9. Repeat steps (2) to (8) for all specified combinations of electrical connections as listed in Table 2.2.1.

Figure 2.2.2 — Dielectric Strength Test Circuit

Figure 2.2.2 — Dielectric Strength Test Circuit (the long description is located below the image)
Description

This image shows the typical set-up for the dielectric strength test. The dielectric strength tester provides an isolated high voltage source from 0 to 1500 volts AC at 60 Hz. One lead of the tester is connected in series with a 50 kΩ variable resistor and a one kΩ resistor. A voltmeter is connected across the 1 kΩ resistor. A second voltmeter is connected across the two leads of the tester, after the 50 kΩ resistor. The two leads are connected to the terminal equipment.

Notes:

  1. A 1500 Vac voltmeter or a resistive voltage divider and high-input impedance voltmeter may be used.
  2. A true root-mean-square (r.m.s.) voltmeter may be used to measure a converted r.m.s. current limit. Alternatively, an oscilloscope may be used to measure peak current. Precautions should be taken, however, to isolate high-voltage differential or current probes.
  3. The 50 kΩ current-limiting resistor is optional but is recommended to reduce the possibility of damage resulting from possible insulation breakdown.
  4. When the TE makes no provision for an external ground, the TE shall be placed on a metal ground plane that has overall dimensions at least 50% greater than the corresponding dimensions of the TE. The TE shall be centrally located on the metal plane. At no point in time should any metal surface of the TE come in contact with the metal plane. If the TE has exposed metal that could come in contact with the metal plane, a thin insulating material shall be inserted between the metal plane and the TE. The metal plane shall be treated as a grounding connection, as defined in Section 2.2.1; however, it shall not be connected to ground.

The introduction of an actual ground connection to the measurement setup may result in erroneous measurement data from most dielectric testers.

2.3 Hazardous Voltage Limitations

2.3.1 Requirements

Under no conceivable condition of TE failure during handling, operation or repair of such equipment or circuitry, shall the open circuit voltage on telephone connections exceed 70 V peak after one second, except for voltages for network control signalling, alerting and supervision.

2.3.2 Type I E&M Leads

TE on the A or B side of the interface (see figures 4.7.1 and 4.7.2) shall comply with the following requirements:

  1. The DC current on the E lead shall not exceed 100 mA.
  2. The maximum DC potentials to ground shall not exceed the values given in Table 2.3.2 when measured across a resistor of 20 kΩ ± 10%.
  3. The maximum AC potential between E&M leads and ground reference shall not exceed 5 V peak.
  4. M lead protection shall be provided to ensure that voltages to ground do not exceed 60 V. For relay contact implementation, a power dissipation capability of 0.5 W shall be provided in the shunt path.
    Table 2.3.2 — Type I E&M
    E LeadM Lead
    TE on B side originates signals to network on E lead± 5 V± 5 V
    TE on A side originates signals to network on M lead−56.5 V; no positive potential w.r.t. ground−56.5 V; no positive potential w.r.t. ground
  5. If the TE contains an inductive component in the E lead, the transient voltage across the contact, as a result of a relay contact opening, shall not exceed the following voltage and duration limitations:
    1. 300 V peak;
    2. a rate of change of 1 volt per microsecond (V/ms); and
    3. a 60 V level after 20 ms.
2.3.2.1 Method of Measurement

For TE intended for connection to Type A or B tie trunks with Type I E&M signalling, which signals to the network on the E lead, A side:

  1. E lead DC current to ground:
    1. Connect the TE as shown in Figure 2.3.3.2(a).
    2. Operate switch S1 to position "b", switch S2 to position "a", switch S3 to position "b".
    3. Set the multimeter to the DC ammeter function.
    4. Measure the DC current from the E lead to ground.
  2. E lead DC voltage to ground:
    1. Connect the TE as shown in Figure 2.3.3.2(a).
    2. Operate switch S2 to position "a", switch S3 to position "a".
    3. Set the multimeter to the DC voltage function.
    4. Operate switch S1 to position "b".
    5. Measure the DC potential between the E lead and ground with the E lead switch in the TE in both the open and closed states.
    6. Repeat step (e) for all other off-hook states of the TE.
  3. E lead AC voltage to ground:
    1. Connect the TE as shown in Figure 2.3.3.2(a).
    2. Operate switch S2 to position "a", switch S3 to position "a".
    3. Set the multimeter to the AC voltage function.
    4. Operate switch S1 to position "b".
    5. Measure the AC potential between the E lead and ground with the E lead switch in the TE in both the open and closed states.
    6. Repeat step (e) for other off-hook states of the TE.

Note:

Repeat steps (2) and (3) and measure the DC and AC voltages at the E lead on the B side.

  1. Contact Protection (only if E lead detector on the A side is inductive):
    1. Verify by examination that protection is provided across the relay winding so as to limit the peak voltage to 300 V.
    2. The rate of change of voltage is 1 V/μs.
    3. The voltage levels off to 60 V or less after 10 ms.

or:

  1. Connect the TE to the test circuit of Figure 2.3.3.2(b).
  2. Open switch S1 and record the oscilloscope trace.

For TE intended for connection to Type A or B tie trunks with Type I E&M signalling, which signals to the network on the M lead, A side:

  1. M lead DC voltage to ground:
    1. Connect the TE as shown in Figure 2.3.3.2(a).
    2. Operate switch S2 to position "a", switch S3 to position "a".
    3. Set the multimeter to the DC voltage function.
    4. Operate switch S1 to position "a".
    5. Measure the DC potential between the M lead and ground with the M lead switch in the TE in both the open and closed states.
    6. Repeat step (e) for other off-hook states of the TE.
  2. M lead AC voltage to ground:
    1. Connect the TE as shown in Figure 2.3.3.2(a).
    2. Operate switch S2 to position "a", switch S3 to position "a".
    3. Set the multimeter to the AC voltage function.
    4. Operate switch S1 to position "a".
    5. Measure the AC potential between the M lead and ground with the E lead switch in the TE in both the open and closed states.
    6. Repeat step (e) for other off-hook states of the TE.

Note:

Repeat steps (1) and (2) and measure the DC and AC voltages at the M lead on the B side.

  1. M lead surge suppression:

Examine a schematic of the E&M circuit and determine whether means are provided to limit the DC voltage to ground to 60 V while giving a power dissipation of 0.5 W.

2.3.3 Type II E&M Leads

TE shall comply with the following requirements:

  1. For TE on the A side of the interface, the DC current in the E lead shall not exceed 100 mA. The maximum AC potential between the E lead and ground shall not exceed 5 V peak.
  2. For TE on the B side of the interface, the DC current in the SB lead shall not exceed 100 mA. The maximum AC potential between the E lead and ground shall not exceed 5 V peak.
  3. The maximum DC potentials to ground shall not exceed the values in Table 2.3.3 when measured across a resistor of 20 kΩ ± 10%.
    Table 2.3.3 — Type II E&M
    E LeadM LeadSB LeadSG Lead
    TE on B side of the interface originates signals to network on E lead.± 5 V± 5 V-56.5 V; no positive potential w.r.t. ground± 5 V
    TE on A side of interface originates signals to network on M lead.-56.5 V; no positive potential w.r.t. ground± 5 V± 5 V± 5 V
  4. The maximum AC potential to ground shall not exceed 5 V peak on the following leads, from sources in the TE:
    1. M, SG and SB leads for TE on the A side of the interface;
    2. E, SG and M leads for TE on the B side of the interface.
  5. If the TE contains an inductive component in the E or M lead, it must ensure that the transient voltage across the contact as a result of a relay contact opening does not exceed the following voltage and duration limitations:
    1. 300 V peak;
    2. a rate of change of 1 V/ms; and
    3. a 60 V level for more than 20 ms.
2.3.3.1 Method of Measurement

For TE intended for connection to Type A or B tie trunks with Type II E&M signalling, which signals to the network on the E lead and SG lead, A side:

  1. E lead DC current to ground:
    1. Connect the TE as shown in Figure 2.3.3.2(a).
    2. Operate switch S1 to position "b", switch S2 to position "a", switch S3 to position "b".
    3. Set the multimeter to the DC ammeter function, grounding the E lead.
    4. Measure the DC current from the E lead to ground.

Note:

Repeat the procedures in step (1) and measure the DC current with the SG lead grounded on the B side.

  1. E lead, SG lead, DC voltage to ground:
    1. Connect the TE as shown in Figure 2.3.3.2(a).
    2. Operate switch S2 to position "a", switch S3 to position "a".
    3. Set the multimeter to the DC voltage function.
    4. Operate switch S1 to position "b".
    5. Measure the DC potential between the lead and ground with the lead switch in the TE in both the open and closed states.
    6. Repeat step (e) for all other off-hook states of the TE.
    7. Operate switch S1 to position "e".
    8. Repeat step (e).
  2. E lead, SG lead, AC voltage to ground:
    1. Connect the TE as shown in Figure 2.3.3.2(a).
    2. Operate switch S2 to position "a", switch S3 to position "a".
    3. Set the multimeter to the AC voltage function.
    4. Operate switch S1 to position "b".
    5. Measure the AC potential between the lead and ground with the lead switch in the TE in both the open and closed states.
    6. Repeat step (e) for all other off-hook states of the TE.
    7. Operate switch S1 to position "e".
    8. Repeat step (e).

    Note:

    Repeat steps (1) and (2) and measure the DC and AC voltages at the E lead and SG lead on the B side.

    1. Contact Protection (only if the E lead detector on the A side is inductive):
      1. Verify by examination, that protection is provided across the relay winding so as to limit the peak voltage to 300 V.
      2. The rate of change of voltage is 1 V/μs.
      3. The voltage levels off to 60 V or less after 20 ms.

    or:

    1. Connect the TE to the test circuit of Figure 2.3.3.2(b).
    2. Open switch S1 and record the oscilloscope trace.

    Note:

    Repeat the measurements in step (4) for the M lead, B side.

For TE intended for connection to Type A or B tie trunks with Type II E&M signalling, which signals to the network on the M lead and SB lead, A side:

  1. M lead, SB lead, DC voltage to ground:
    1. Connect the TE as shown in Figure 2.3.3.2(a).
    2. Operate switch S2 to position "a", switch S3 to position "a".
    3. Set the multimeter to the DC voltage function.
    4. Operate switch S1 to position "a".
    5. Measure the DC potential between the M lead and ground with the M lead switch in the TE in both the open and closed states.
    6. Repeat step (e) for all other off-hook states of the TE.
    7. Operate switch S1 to position "d".
    8. Repeat step (e).
  2. M lead, SB lead, AC voltage to ground:
    1. Connect the TE as shown in Figure 2.3.3.2(a).
    2. Operate switch S2 to position "a", switch S3 to position "a".
    3. Set the multimeter to the AC voltage function.
    4. Operate switch S1 to position "a".
    5. Measure the AC potential between the M lead and ground with the M lead switch in the TE in both the open and closed states.
    6. Repeat step (e) for all other off-hook states of the TE.
    7. Operate switch S1 to position "d".
    8. Repeat step (e).

Note:

Repeat steps (1) and (2) and measure the DC and AC voltages at the M lead on the B side.

2.3.3.2 Summary of Measurements
Table 2.3.3.2 — E&M Leads to be Tested
Interface TypeType IType II
Side of the InterfaceABAB
Lead to be TestedEMEMESGMSBESGMSB
1DC Current to GroundXXX
2AC Volts to GroundXXXXXXXXXXXX
3DC Volts to GroundXXXXXXXXXXXX
4Open Circuit Volts to Ground
5Surge SuppressionX
6Contact ProtectionXXX

Figure 2.3.3.2(a) — Metallic Potential Test Circuit

Figure 2.3.3.2(a) — Metallic Potential Test Circuit (the long description is located below the image)
Description

This image shows the typical set-up for measuring the voltage potentials found on tie trunk interfaces. A multimeter is used to perform the required measurements. It is connected to ground via a switch, S2 position "a", or to the ring lead of a Type C tie trunk or off-premises station, OPS, interface, S2 position "b". A 20 kΩ resistor can be connected in parallel with the multi-meter via a switch, S3 position "a". The other multimeter lead is connected to a range of different tie trunk interface leads via a six-position switch, S1. The configurations of the switches are determined by the applicable measurement methods found in Section 2.3.3.2.

Notes: 

  1. The input resistance of the voltmeter shall not be less than 200 kΩ.
  2. When the TE makes provision for an external connection to ground (G), the TE shall be connected to ground. When the TE makes no provision for an external ground, the TE shall be placed on a ground plane which is connected to ground and has overall dimensions at least 50% greater than the corresponding dimensions of the TE. The TE shall be centrally located on the ground plane without any additional connection to ground. At no point in time should any metal surface of the TE come in contact with the ground plane. If the TE has exposed metal that could come in contact with the metal ground plane, a thin insulating material shall be inserted between the ground plane and the TE.

Figure 2.3.3.2(b) — E or M Lead Contact Protection

Figure 2.3.3.2(b) — E or M Lead Contact Protection (the long description is located below the image)
Description

This image shows the typical set-up for measuring the contact bounce of the E&M lead relay. The E&M lead of the terminal equipment is connected to a storage scope. A switch, S1, connects the E&M lead to the ground connector of the storage scope.

Notes:

  1. S1 consists of relay contacts that are designed to be free of contact bounce, such as those found in a mercury-wetted relay.
  2. When the TE makes provision for an external connection to ground (G), the TE shall be connected to ground. When the TE makes no provision for an external ground, the TE shall be placed on a ground plane which is connected to ground and has overall dimensions at least 50% greater than the corresponding dimensions of the TE. The TE shall be centrally located on the ground plane without any additional connection to ground. At no point in time should any metal surface of the TE come in contact with the ground plane. If the TE has exposed metal that could come in contact with the metal ground plane, a thin insulating material shall be inserted between the ground plane and the TE.

2.3.4 Off-premises Station (OPS) and Direct Inward Dialling (DID) Interfaces Voltages

  1. Talking battery or voltages applied by a PBX (or similar system) to OPS and DID interface leads for the purpose of supervision must be negative with respect to ground, shall not exceed -56.5 Vdc and shall not have a significant AC component.*

    * The AC component should not exceed 5 V peak unless otherwise specified in Section 3.4.

  2. Ringing signals applied by a PBX (or similar system) to OPS interface leads shall comply with requirements in Section 2.3.9.4. Ringing voltages shall be applied between the ring conductor and ground.
2.3.4.1 Method of Measurement

For TE intended for connection to OPS lines or DID Trunks:

  1. Tip to ring, tip to ground, ring to ground, DC measurements:
    1. Connect the TE as shown in Figure 2.3.3.2(a).
    2. Operate switch S1 to position "c", switch S2 to position "b", and switch S3 to position "b".
    3. Set the multimeter function to DC volts.
    4. Measure the DC potential across tip and ring.
    5. Operate switch S2 to position "a".
    6. Measure the DC potential between tip and ground.
    7. Operate switch S1 to position "f".
    8. Measure the DC potential between ring and ground.
    9. Repeat steps (c) to (h) for all other on-hook states of the TE.
  2. Tip to ring, tip to ground, ring to ground, applied ringing, AC measurements (OPS Line):
    1. Connect the TE as shown in Figure 2.3.3.2(a).
    2. Operate switch S1 to position "c", switch S2 to position "b", and switch S3 to position "b".
    3. Set the multimeter function to AC volts.
    4. Measure the AC potential across tip and ring.
    5. Operate switch S2 to position "a".
    6. Measure the AC potential between tip and ground.
    7. Operate switch S1 to position "f".
    8. Measure the AC potential between ring and ground.
    9. Repeat steps (c) to (h) for all other on-hook states of the TE including applied ringing.

Note:

Perform the tests specified in Section 2.3.9 to verify compliance with ringing source requirements.

2.3.4.2 Summary of Measurements
  1. In the idle open circuit state, measure the DC voltage with the DC voltmeter connected between:
    1. tip and ring;
    2. tip and ground; and
    3. ring and ground.
  2. In the idle open circuit state, measure the extraneous AC voltage with an AC voltmeter connected between:
    1. tip and ring;
    2. tip and ground; and
    3. ring and ground.
  3. In the ringing open circuit state, confirm that the ringing signal is applied to the proper lead by measuring the AC voltage with the AC voltmeter connected between:
    1. tip (OPS) and ground – for OPS leads only; and
    2. ring (OPS) and ground – for OPS leads only.
  4. Perform the tests specified in Section 2.3.9 to verify compliance with ringing source requirements.

2.3.5 Local Area Data Channel (LADC) interfaces

For local area data channel (LADC) interfaces, during normal operating modes that include TE initiated maintenance signals, approved TE shall, except during the application of ringing (limitations specified in Section 2.3.9) with respect to telephone connections (tip, ring, tip_1, ring_1), ensure that:

  1. Under normal operating conditions, the r.m.s. current per conductor between short-circuited conductors, including DC and AC components, does not exceed 350 mA. For other than normal operating conditions, the r.m.s. current between any conductor and ground or between short circuited conductors, including DC and AC components, may not exceed 350 mA for more than 1.5 minutes;
  2. The DC voltage between any conductor and ground does not exceed 60 V. Under normal operating conditions, it shall not be positive with respect to ground (though positive voltages up to 60 V may be allowed during brief maintenance states);
  3. AC voltages are less than 42.4 Vp between any conductor and ground. TE shall comply while other interface leads are:
    1. unterminated, and
    2. individually terminated to ground.

Note:

Combined AC and DC voltages between any conductor and ground shall be less than 42.4 Vp when the absolute value of the DC component is less than 21.2 V, and less than (32.8 + 0.454 x Vdc) when the absolute value of the DC component is between 21.2 and 60 V.

2.3.5.1 Method of Measurement

Be advised:

Adequate safety precautions should be observed.

  1. Place TE in first operating state.
  2. Connect current meter between T and R leads of the TE and measure combined AC and DC short circuit current.
  3. Repeat step (2) with current meter between T and ground and between R and ground.
  4. Repeat steps (1) to (3) for the T1 and R1 pair of the TE if testing a 4-wire interface.
  5. Connect DC voltmeter between T and ground and measure voltage.
  6. Repeat step (5) with voltmeter between R and ground.
  7. Repeat steps (5) and (6) for the T1 and R1 pair if testing a 4-wire interface.
  8. Connect oscilloscope between T lead and ground, and measure AC peak and combined AC peak and DC voltages with other unterminated network leads.
  9. Repeat step (8) with oscilloscope between R and ground.
  10. Repeat steps (8) and (9) for the T1 and R1 pair if testing a 4-wire interface.
  11. Repeat steps (8) to (10) for AC peak voltage only with other network leads that are individually terminated to ground.
  12. Repeat steps (2) to (11) for other modes of operation.
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