Nortel DMS-100 Series General Description Manual

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Nortel DMS-100 Series General Description Manual Manual pdf 89 page image

Ringing in Series II peripherals 3-21DMS-100 Ringing SystemANI/coin signalsANI/coin signals are transmitted from the NT6X53 on a two-wire bus, but,unlike bridged ringing signals, they are not returned in the loop. InsteadANI/coin signals are directed to ground at the subscriber premises and currentis recovered at the ground window of the central office. ANI/coin signals maybe applied to both tip and ring together or just to the tip lead.Automatic number identification is a system whereby a calling number isidentified automatically and transmitted to the automatic message accounting(AMA) office equipment for billing. The ringing generator provides fourvoltages for ANI/coin functions. The ANI function uses +48 V and -48 V toidentify individual parties on a party line of up to four parties. Coin phones use+130 V to indicate coin collect operations, -130 V to indicate coin return, and-48 V for a coin presence test.As shown in Figure 3-6, "Detailed ringing schematic" on page 3-18 theringing system supports separate ringing and ANI/coin buses from the ringinggenerator to the line drawers. However, at the drawer level, only one bus isused to send either ANI/coin or ringing signals to the line drawers. Unlikeringing signals, ANI/coin signals from both ringing generators are notselectable within the NT6X53 power converter. Ringing generator 0 providesANI/coin voltages for LCM unit 0, and ringing generator 1 provides ANI/coinvoltages for LCM unit 1. If a failure occurs in the ANI/coin circuitry on theringing generator, the LCM unit it serves enters a system-busy state, forcingthe remaining LCM unit to go into takeover mode. The unit in takeover nowsupplies ANI/coin and ringing signals to all drawers in the LCM.Relay K1 on the power converter selects between positive and negativevoltages; this function is driven by the SPOL (select polarity) control signalshown in the figure "Status and control bits for LCM ringing". Relay K2selects between 48 V dc and 130 V dc and is driven by control signal SVOLT(select voltage) shown in the Figure 3-7, "Status and control bits for LCMringing" on page 3-20 Relay K3 (SCOIN control signal in Figure 3-7, "Statusand control bits for LCM ringing.") selects between applying voltage on the tipand ring leads together or only on the tip lead. For 48 V selections, a tip-onlyapplication is provided through resistor R49.As shown in Figure 3-6, "Detailed ringing schematic" on page 3-18 all currentfrom ANI/coin sources is routed through a current detector. This circuit sendsa signal to the NT6X51 processor card indicating either the presence orabsence of current on the ANI/coin bus. This method is used by the processorto make decisions about coin presence tests and automatic numberidentification.