156 NT1R20 Off-Premise Station Analog Line card• The attenuation distortion (frequency response) of the OPS facilityshould be within ±3.0 dB over the frequency range from 300 to 3000 Hz.It is desirable that this bandwidth extend from 200 to 3200 Hz.• The terminating impedance of the facility at the OPS port shouldapproximate that of 600 ohm cable.If the OPS line facility loss is greater than 4.5 dB but does not exceed 15dB, line treatment using a switched-gain voice frequency repeater (VFR)extends the voice range.The overall range achievable on an OPS line facility is limited by thesignaling range (2300 ohm loop including telephone set resistance).Signaling range is unaffected by gain treatment; so gain treatment canbe used to extend the voice range to the limit of the signaling range. Forexample, on 26 AWG wire, the signaling range of 2300 ohms correspondsto an untreated metallic loop loss of 15 dB. Gain treatment (such as a VFR)with 10.5 dB of gain would maintain the OPS service loss objective of 4.5dB while extending the voice range to the full limit of the signaling range:• 15 dB (loss corresponding to the maximum signaling range)• – 4.5 dB (OPS service loss objective)• = 10.5 dB (required gain treatment)The use of dial long line units to extend signaling range of OPS analog linecards beyond 15 dB is not recommended.Loss is inserted between OPS analog line card ports and other ports inaccordance with the loss plan. This plan determines the port-to-port lossfor each call. When a port is configured for CLS OPS, loss is programmedinto the OPS analog line card on a call-by-call basis. When configured forCLS ONS, an OPS analog line card port is programmed to a value that isfixed for all calls. The loss in the other port involved in the call can vary on acall-by-call basis to achieve the total loss scheduled by the plan.For satisfactory transmission performance, particularly on connectionsbetween the public network and an OPS termination, it is recommendedthat facilities conform to the following:• Total 1 kHz loss from the local serving CO to the OPS terminal shouldnot exceed 7.0 dB. The total loss in the facility between the PBX and theterminal must not exceed 4.5 dB. See Figure 91 "NTCK80AA/AB/AC/AD"(page 338). The following requirements are based on historic insertedconnection loss (ICL) objectives:— PBX – CO trunk: 5 dB with gain; 0 – 4.0 dB without gain— OPS line: 4.0 dB with gain; 0 – 4.5 dB without gain Economic andtechnological changes led to modifications of these objectives. Butsince the loss provisions in the PBX for OPS are constrained byNortel Communication Server 1000Circuit Card ReferenceNN43001-311 01.04 StandardRelease 5.0 23 May 2008Copyright © 2003-2008, Nortel Networks.
