Nortel Networks 311 External Alarm Connections, MMI Connections

Installation 285

For 75 ohm coaxial installations, E1 signaling for all 30 channels is

transmitted over P2 connector pins 1, 3, 9, and 11 though an adapter and

out two coaxial connectors Tx (transmit) and Rx (receive). Tx is the LEI

output, and Rx is the LEI input from the E1 stream. E1 transmit and receive

pairs must be turned over between the LEI and the CPE that is hardwired

without carrier facilities. If the LEI is connected through E1 carrier facilities,

the transmit and receive pairs must be wired straight through to the RJ48

at the Telcodemarc, the LTU, or other E1 carrier equipment. The E1 CPE

at the far end has Tx and Rx wired straight from the RJ48 demarc at the

far end of the carrier facility.

External Alarm Connections

P3 connector pins 1, 2 and 3 can be plugged into any external alarm-sensing

hardware. Plug the DB9 male connector labeled "P3" into an external

alarm. These connections are optional, and the LEI functionality is not

affected if they are not made.

The MMI monitors the E1 link for speciﬁed performance criteria and reports

on problems detected. One of the ways it can report information is through

this external alarm connection. If connected, the LEI’s microprocessor

activates the external alarm hardware if it detects certain E1 link problems it

has classiﬁed as alarm levels 1 or 2. See "Man-Machine E1 maintenance

interface software" (page 292) for a detailed description of alarm levels and

conﬁguration. If an alarm level 1 or 2 is detected by the MMI, the LEI closes

the contact that is normally open, and opens the contact that is normally

closed. The MMI command "Clear Alarm" retur ns the alarm contacts to

their normal state.

MMI Connections

P5 connector pins 2, 3, 5, 7 and 9 are used to connect the LEI to the MMI

terminal, connecting LEIs in a daisy chain for access to a shared MMI

terminal. When logging into a LEI, "control 2" is assertedby that card,which

informs all of the other cards not to talk on the bus, but ratherto pass the

data straight through. The pins labeled "control 1" are reserved for future

use. As with the external alarm connections, MMI connections are optional.

Up to 128 LEIs can be linked, located in up to 16 separate IPE shelves, to

one MMI terminal using the daisy chain approach.

If only one LEI is installed, cable from the DB9 male connector labeled "P5"

(toward MMI terminal) to one of the COM ports on the back of any TTY,a

PC running a terminal emulation program, or a modem. For installations of

only one card, no connection is made to the DB9 female connector labeled

"P4" (away from MMI terminal).

If two or more LEIs are being installed into the system, the MMI port

connections can be daisy-chained together so that only one MMI terminal

is required for up to 128 LEIs. See Figure 60 "LEI card - connecting two

Nortel Communication Server 1000

Circuit Card Reference

NN43001-311 01.04 Standard

Release 5.0 23 May 2008