| (A) Each DCTU must provide and maintain interoffice
trunks on its portion of the local exchange service network so that
97% of the interoffice local calls excluding calls between central
offices in the same building are completed without encountering equipment
busy conditions or equipment failures. For a DCTU's testing, record-keeping,
and reporting purposes, the DCTU is not required to separate local
dial service results from local interoffice dial service results unless
specifically requested by the commission.
(B) The availability factor for stored program controlled
digital and analog switching and interoffice transmission facilities
for end-to-end transmission must be 99.93%, or the total unscheduled
outage must not exceed 365 minutes per year.
(C) For any exchange that falls below the established
performance objective level, a report detailing the cause and proposed
corrective action for the local dial service measures, must be submitted
to the commission.
(5) Direct distance dial service. Engineering and maintenance
of the trunk and related switching components in the toll network
must permit 97% completion on properly dialed calls, without encountering
failure because of network congestion or blockages, or equipment irregularities.
For any exchange that falls below the established performance objective
level, the DCTU must submit to the commission a report detailing the
cause and proposed corrective action for the direct distance dial
service measure.
(6) Customer trouble reports.
(A) A DCTU that serves more than 10,000 access lines
must maintain its network service in a manner that ensures the DCTU
receives no more than three customer trouble reports on a company-wide
basis, excluding customer premises equipment (CPE) reports, per 100
customer access lines per month on average. Performance Benchmark
Applicable for Corrective Action: If the customer trouble report exceeds
3.0%, or three per 100 access lines, for a large exchange or 6.0%,
or six per 100 access lines, for a small exchange for three consecutive
months, the DCTU must provide a detailed corrective action plan for
such an exchange or wire center. For purposes of this section, a large
exchange is defined as an exchange serving 10,000 or more access lines
and a small exchange is defined as an exchange serving less than 10,000
access lines.
(B) A DCTU that serves 10,000 or less access lines
must maintain its network service in a manner that ensures the DCTU
receives no more than six customer trouble reports on a company-wide
basis, excluding CPE reports, per 100 customer access lines per month
on average. Performance Benchmark Applicable for Corrective Action.
If the customer trouble report exceeds 6.0%, or six per 100 access
lines per exchange for three consecutive months, the DCTU must provide
a detailed corrective action plan for such an exchange or wire center.
(C) The DCTU must provide to the customer a commitment
date by which the trouble will be cleared. If a premises visit is
required, the DCTU must schedule an appointment period with the customer
for the morning or afternoon, not to exceed a four hour time period,
on the commitment date. If the DCTU cannot keep an appointment, the
DCTU must attempt to notify the customer by a telephone call and schedule
a new appointment. If unable to gain access to the customer's premises
during the scheduled appointment period, the DCTU representative must
leave a notice at the premises advising the customer how to reschedule
the work.
(D) At least 90% of out-of-service trouble reports
on service provided by a DCTU must be cleared within eight hours,
except where access to the customer's premises is required but unavailable
or where interruptions are caused by a force majeure affecting large
groups of customers. Performance Benchmark Applicable for Corrective
Action: If the performance is below 90% in any exchange area for a
period of three consecutive months, the DCTU must provide a detailed
corrective action plan for such an exchange or wire center.
(E) Each DCTU must establish procedures to ensure the
prompt investigation and correction of trouble reports so that the
percentage of repeated trouble reports on residence and single line
business lines does not exceed 22% of the total customer trouble reports
on those lines. Performance Benchmark Applicable for Corrective Action:
If repeat reports exceed 22% of the total customer trouble report
in any exchange for three consecutive months, the DCTU must provide
a detailed corrective action plan for such an exchange or wire center.
(7) Transmission requirements. All voice-grade trunk
facilities must conform to accepted transmission design factors and
must be maintained to meet the following objectives when measured
from line terminals of the originating central office to the line
terminals of the terminating central office. A periodic report for
central offices or exchanges as requested by the commission staff
must be provided by the DCTU to demonstrate compliance with the following
objectives.
(A) Interoffice local exchange service calls. Excluding
calls between central offices in the same building, 95% of the measurements
on the network of a DCTU should have a C-message weighting between
two to ten decibels loss at 1000+20 hertz and no more than 30 decibels
above reference noise level.
(B) Direct distance dialing. Ninety-five percent of
the transmission measurements should have a C-message weighting from
three to 12 decibels loss at 1000+20 hertz and no more than 33 decibels
above reference noise level.
(C) Subscriber lines. All newly constructed and rebuilt
subscriber lines must be designed for a transmission loss of no more
than eight decibels from the serving central office to the customer
premises network interface. All subscriber lines must be maintained
so that transmission loss does not exceed ten decibels. Subscriber
lines must in addition be constructed and maintained so that metallic
noise does not exceed a C-message weighting of 30 decibels above reference
noise level on 90% of the lines. Metallic noise must not exceed a
C-message weighting of 35 decibels above reference noise level on
any subscriber line.
(D) Private Branch Exchange (PBX), key, and multiline
trunk circuits. PBX, key, and multiline trunk circuits must be designed
and maintained so that transmission loss at the subscriber station
does not exceed eight decibels. If the PBX or other terminating equipment
is customer-owned and, if transmission loss exceeds eight decibels,
the DCTU's responsibility is limited to providing a trunk circuit
with no more than five decibels loss from the central office to the
point of connection with the customer's facilities.
(E) Impulse Noise Limits. The requirements for impulse
noise limits are as follows:
(i) For switching offices, the noise level count must
not exceed five pulses above the threshold in any continuous five
minute period on 50% of test calls. The reference noise level threshold
must be less than: 54 decibels above reference noise with C-message
weighting (dBrnC) for a Crossbar switch, 59 dBrnC for a step-by-step
switch, and 47 dBrnC for a electronic or digital switch.
(ii) For trunks, the noise level count must not exceed
five pulses above the threshold in any continuous five minute period
on 50% of trunks in a group. The reference noise level threshold must
be less than 54 dBrnC at a zero transmission level point (dBrnC0)
for voice frequency trunks, and 62 dBrnC0 for digital trunks.
(iii) For loop facilities, the noise level count must
not exceed 15 pulses above the threshold in any continuous 15 minute
period on any loop. The reference noise level threshold must be less
than 59 dBrnC when measured at the central office, or referred to
the central office through 1004 Hz loss.
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| Source Note: The provisions of this §26.54 adopted to be effective May 15, 2000, 25 TexReg 4319; amended to be effective August 14, 2005, 30 TexReg 4473; amended to be effective November 29, 2007, 32 TexReg 8468; amended to be effective April 4, 2012, 37 TexReg 2178; amended to be effective December 21, 2023, 48 TexReg 7524 |
