Nortel Networks 553-3001-211 manual Carrier Shield grounding Switch SW4

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Carrier Shield grounding (Switch SW4)

Table 248 lists the Carrier Shield ground switch settings.

Table 248

Carrier Shield grounding switch settings

Switch	Down (On)	Up (Off)
SW 4 – 1	Rx – FGND	Rx – OPEN
SW 4 – 2	Tx – FGND	Tx – OPEN

Note: The usual method is to ground the outer conductor of the receive coax signal.

Receiver functions

The receiver extracts data and clock from an AMI (Alternate Mark Inversion) coded signal and outputs clock and synchronized data. The receiver is sensitive to signals over the entire range of cable lengths and requires no equalization. The clock and data recovery meets or exceeds the jitter specifications of the CCITT recommendation G.823 and the jitter attenuation requirements of the CCITT recommendation G.742. This provides jitter attenuation increasing from 0 dB to 60 dB over the frequency range from about 6 Hz to 6 KHz.

Transmitter functions

The transmitter takes the binary (dual unipolar) data from the PCM transceiver and produces bipolar pulses. This conforms to CCITT recommendation G.703 pulse shape.

Loopbacks

The remote loopback function causes the far-end device to transmit the same data that it receives, using the jitter attenuated receive clock. The data is additionally available at the far-end receive data outputs. Local loopback causes the transmit data and clock to appear at the near-end clock and receive data outputs. This data is also transmitted on the line unless an Alarm Indication Signal (AIS) is transmitted instead.

553-3001-211 Standard 2.00 September 2004