Nortel Networks Circuit Card - Manual (Page 258)

Page 258 of 906 NT5D33 and NT5D34 Lineside E1 Interface cards
553-3001-211 Standard 3.00 August 2005
E1 interface circuit
The LEI contains one E1 line-interface circuit which provides 30 individually
configurable voice interfaces to one E1 link in 30 different time slots. The
circuit demultiplexes the 2.56 Mbps DS-30X transmit signaling bitstreams
from the DS-30X network loop and converts it into 2.048 mHz E1 transmit
signaling bitstreams onto the E1 link. It also does the opposite, receiving
receive signaling bitstreams from the E1 link and transmitting receive
signaling bitstreams onto the DS-30X network loop.
The E1 interface circuit provides the following:
• An industry standard CEPT (0 to 655 feet) interface
• DS-30X signaling protocol into FXO A- and B-channel-associated
signaling protocol
• Switch-selectable transmission and reception of E1 signaling messages
over an E1 link in either loop or ground start mode
• Switch-selectable call processing between the Australian P2, North
American Standard, or other user-configurable schemes
Signaling and control
The LEI also contains signaling and control circuits that establish, supervise,
and take down call connections. These circuits work with the system
controller to operate the E1 line interface circuit during calls. The circuits
receive outgoing call signaling messages from the controller and return
incoming call status information to the controller over the DS-30X network
loop.
Card control functions
Control functions are provided by a microcontroller and a card LAN link on
the LEI. A sanity timer is provided to automatically reset the card if the
microcontroller stops functioning for any reason.
Microcontrollers
The LEI contains a microcontroller that controls the internal operation of the
card and the serial card LAN link to the controller card. The microcontroller
controls the following:
• reporting to the CE CP through the card LAN link