Zhone Technologies Network Device manual Foreign Exchange Station FXS Card, VF Transmission

Zhone Technologies, Inc. IMACS Product Book, Version 4

III. IMACS Voice Modules and Applications

1. Foreign Exchange Station (FXS) Card

The IMACS supports one Foreign Exchange Station (FXS) card, the 812960 FXS Card, which provides eight 2-wire analog ports with a terminating impedance of 600 ohms.

FXS cards can be installed in any IMACS chassis User Slot, and will (in most cases) require a ring generator. AC powered systems will also require a –48 VDC converter. FXS cards encode the incoming analog voice signals into 64 Kbps PCM format before transmission onto the network. Each FXS card provides a single 50-pin female amphenol connector (RJ27X).

All port parameters are software configurable on a port-by-port basis. The Mode setting specifies whether the port is to be used for standard Foreign Exchange Station, Foreign Exchange Software Defined Network (“wink”), Private Line Automatic Ringdown (PLAR), or Dial Pulse Origination applications. For example in the case of a PLAR circuit, the port can be programmed to provide Ringback Tone towards the caller. The Type setting specifies Loop Start, Loop Start with Forward Disconnect, Ground Start, Ground Start Immediate and Ground Start Automatic operation. If the PLAR mode is selected, then the two options supported under Type are “D3” and “D4” which meet the pre-1988 and post-1988 specifications for PLAR circuits. The PCM Coding options supported include ∝ -Law, A-Law and inverted A-Law, and the user may also select the Trunk Conditioning mode (busy or idle) that should be applied towards the attached equipment should the WAN facility that the port is connected to fails. In addition, both the Transmit (Tx) and Receive (Rx) TLP levels can be set in increments of 0.1 dB. The Tx TLP range is from -10.0 dB to +5.0 dB. The Rx TLP range is from -10.0 dB to +2.0 dB.

The user may also specify, on a port-by-port basis, whether to use North American ANSI standard ABCD signaling (which is the default) or ITU (CCITT) ABCD signaling by turning the signaling conversion setting “on” or “off”. The trans-hybrid balance may be specified as one of eight values as well as for a customized user-specified terminating impedance. At the present time, all eight values are identical and are set for a terminating impedance of 600+2.15µF in the case of a Model 8129 FXS card.

Software-initiated testing and diagnostics supported on FXS cards include the setting of both analog and digital loop back towards the network and the generation of a Digital MilliWatt (DMW) signal on a port-by-port basis. A robust set of Test functions allow the user to monitor and set the state of the analog Tip and Ring leads of any FXS port and to set and monitor the state of the ABCD signaling bits of the digitized voice signal. In cross-connect systems, the Test functionality also includes the ability to generate test tones (300Hz, 1 kHz, 3 kHz and “quiet”) and transmit those toward either the user side or the network side of the system. FXS cards can use the voice-compression features of the ADPCM and LBRV Server cards. Table 10 provides all the relevant FXS cards specifications.

Table 10—FXS Specifications

	Model 8129 2-wire Analog FXS Voice Card
	Physical Characteristics
	Model 812960	8 ports
	Physical Interface	1 female 50-pin Telco connector
	Dimensions of Card	8 x 0.94 x 7.48 inches (HWD)
	Weight of Card	1 lb or .4 k
	Power Consumption of Card	3.12 W
	Signaling Modes	Software configurable on a per port basis: foreign exchange station
		(FXS), FXS defined network (Megacom), Private Line Automatic
		Ringdown (PLAR), Dial Pulse Originating (DPO)
	Signaling Types	Loop Start, Ground Start,	Loop Start with Forward Disconnect, Feature
		Group D (for high-speed modem services), Bill On Answer, D3, D4,
		DPO and Single Party, Universal Grade Voice
	Specification	Short Loop		Long Loop
	Loop Resistance	Min 300 Ω, Max 700 Ω		Min 300 Ω , Max 1800 Ω
	Termination Impedance	600 + 2.16 uF
	VF Transmission
March 2001				Page 32