Nortel SL-100 Product Manual

Also see for Meridian SL-100: User guide User guide Reference guide Fundamentals Reference manual

Contents

Nortel SL-100 Product Manual Manual pdf 91 page image

Site level power and grounding 91Communication link groundingThe isolated bonding network must be protected from grounds associatedwith external communications links. The communications links mustbe isolated to address both operational concerns and safety concerns.Operational and safety concerns include signals that are referenced todifferent ground potentials, which can cause signal errors and circuitdamage, and metallic connections that allow contact between differentground potentials.The four types of external communications links used with the MeridianSL-100 system are fiber optic links, EIA-232 links, shielded twisted pair linksand coaxial links. The Meridian SL-100 system supports all four types oflinks with the following constraints:• Fiber optic links must have metallic components, such as metallicstrengthening members, connected at both ends.• EIA-232 must be isolated using back-to-back modems, opto-isolators oran equivalent approved isolation device (except when it interfaces withan Input/Output Module). EIA-232 cables should not extend beyond theimmediate IBN area. Both synchronous and asynchronous EIA-232links can be isolated using fiber optic modems.• Shielded twisted pair signals must be transformer-coupled. EMIcompliant links must bond the cable shield to the frame ground onthe Meridian SL-100 system, to the Transmission Bonding Bar (TBB)if extending beyond the IBN area, and at the end of the link. EMInoncompliant links (such as an Ethernet link) must bond the cable shieldto the frame ground at the sending end of the link and must be open atthe receiving end of the link.• External coaxial links must be AC-coupled with the high voltageprotection of the center conductor. (Transformer coupling isrecommended.) The cable shield must be bonded to the IBN groundreference with a TBB and to the frame ground of the Meridian SL-100system. The shield of internal coaxial links must not be referenced tothe system logic return.Workstation, printer, and modem power and groundingExternal devices such as MAP workstations, printers, modems and digitalcarrier trunk interfaces must be isolated from external grounding systems.Workstations and printers, and modems located with a workstation orprinter, must not be powered from an internal power source (embeddedinverter). Workstations, printers, and collocated modems can be poweredby a CBN source such as commercial AC, Uninterruptible Power Source(UPS), external inverter derived AC or another acceptable AC source.Communication Server 2100Meridian SL-100 Product Guide555-4001-103 20.01 StandardSE09 20 October 2006Copyright © 2006, Nortel Networks Nortel Networks Confidential.