Nortel Networks Video Gaming Accessories 553-3001-211 Manual De Usuario

Descargar
Página de 896
 NT8D15 E&M Trunk card
 Page 621 of 894
Card interfaces
The E&M trunk card passes voice and signaling data over DS-30X loops and 
maintenance data over the card LAN link. 
The E&M trunk card contains four identical and independently configurable 
trunk interface units (also referred to as circuits). Each unit provides 
impedance matching and a balance network in a signal transformer/analog 
hybrid circuit. Also provided are relays for placing outgoing call signaling 
onto the trunk. Signal detection circuits monitor incoming call signaling. A 
CODEC performs A/D and D/A conversion of trunk analog voiceband 
signals to digital PCM signals. 
The four units on the card can operate in the A-Law or the µ-Law companding 
mode. The mode is selected by making service change entries. Each unit can 
be independently configured for 2-wire E&M, 4-wire E&M, and paging trunk 
types. The trunk type is selected by service change entries and jumper strap 
settings. All units on the card can perform the following features:
convert transmission signals from analog-to-digital and digital-to-analog
provide outpulsing on the card: make/break ratios are defined in software 
and downloaded at power-up and by software command
provide 600-ohms balance and termination impedance (2-wire 
configuration)
provide 600-ohms termination impedance (4-wire configuration)
provide pad control for 2-wire and 4-wire facility connections
enable trunk type and function to be configured on a per-port basis in 
software
provide isolation of foreign potentials from transmission and signaling 
circuit
provide software control of A-Law and µ-Law modes
support loopback of pulse code modulation (PCM) signals to DS-30X for 
diagnostic purposes