Download TR41.9.2-05-02-007 - Telecommunications Industry Association

TR41.9.2-05-02-007
Title: Proposal to revise TSB31-C, Section 8.6, Ringdown Voiceband Private
Line and Metallic Channel Interface
Distribution to: TIA TR41.9.2
Meeting Location: Las Vegas, NV
February 7, 2005
Submitting
Organization: Cisco Systems, Inc.
Contact Tim Lawler
Information: Cisco Systems, Inc.
170 West Tasman Dr.
San Jose, CA 95134
Phone: (408) 527-0681
Fax: (408) 526-4184
Email: [email protected]
Keywords: Part 68, TIA/TSB-31-C
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TR41.9.2-05-02-007
8.6
Ringdown Voiceband Private Line and Metallic Channel Interface
TIA-968-A, 4.4.1.7
8.6.1 Background
Voiceband private lines referred to in this requirement provide a dedicated voice
channel with signaling capability between two or more customer premises. The facility
may be either two-wire or four-wire and is usually referred to by the type of signaling
between locations (points). Thus, there are two-point and multipoint private lines. Twoway ringdown, or simply "ringdown," is one of the signaling methods used for such
private lines. The signaling range can be extended by converting to an inband signaling
tone referred to as single-frequency signaling. A metallic facility referred to in this
requirement is simply a pair or two pairs of wires with no restriction on the type of
signaling that can be used. Two-way ringdown relies solely on the application of ringing
voltage at either end of the private line for alerting the other end. Battery is not required
for voice transmission, but dc monitoring voltage, as defined in Section 8.8.1, may be
present. The short circuit limit for both ringdown and metallic private lines is consistent
with the maximum current capabilities of most load coils that may be on the line.
8.6.2 Purpose
To verify that voltages and currents appearing at ringdown and metallic private line
interfaces are not hazardous to personnel or equipment.
8.6.3 Equipment
(1)
DC current meter SEL# 19.
(2)
DC voltmeter SEL# 22.
NOTE: Refer to Section 5.3 for equipment details.
8.6.4 Equipment States Subject to Test
(1)
Idle.
(2)
Talking.
(3)
Signaling.
8.6.5 Procedure
WARNING! ADEQUATE SAFETY PRECAUTIONS SHOULD BE OBSERVED!
TR41.9.2-05-02-007
Inspect appropriate circuit diagrams to verify the following:
(1)
Ringing voltage is applied to the R lead with the T lead grounded for two-wire
interfaces;
(2)
Ringing voltage is simplexed on the T and R leads, and ground is simplexed on the
T1 and R1 leads for four-wire interfaces.
(3)
Perform tests specified in Section 8.8.5 to verify compliance with ringing source
requirements in the signaling state.
(4)
Place EUT in the idle state.
(5)
Connect dc voltmeter between T lead and ground of the EUT, and measure the
voltage, noting polarity.
(6)
Repeat Step (4) for R lead.
(7)
Repeat Step (4) and Step (5) for T1 and R1 leads of the EUT if testing a four-wire
interface.
(8)
Repeat Step (3) through Step (6) with EUT in the talking state.
(9)
Place EUT in idle state.
(10)
Connect current meter between T and R leads, and measure short circuit current.
(11)
Repeat Step (9) between T lead and ground and between R lead and ground.
(12)
Repeat Step (9) for T1 and R1 leads if testing a four-wire interface.
(13)
Repeat Step (9) through Step (11) for talking state.
8.6.6 Alternative Methods
None suggested.
8.6.7 Suggested Test Data
Brief written analysis of observed ringing circuit arrangements verifying the following: (i)
ringing is used for alerting only, (ii) ringing voltage is applied to R lead, and (iii) ringing
voltage is simplexed on T and R leads.
(1)
DC voltages during idle and talking states:
(a)
T to ground;
TR41.9.2-05-02-007
(2)
(b)
R to ground;
(c)
T1 to ground;
(d)
R1 to ground.
DC current during idle and talking states:
(a)
T to R;
(b)
T to ground;
(c)
R to ground;
(d)
T1 to R1;
(e)
T1 to ground;
(f)
R1 to ground.
8.6.8 Comments
Refer to TIA-968-A Section 4.4.3 for the definition of non-hazardous voltage.