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2.3.
SYNCHRONISED CLOCK OUTPUTS
The NSE supplies six (6) ITU TG.703/10 (120Ω) output clocks. These can be used for
E-10B exchanges and C-DOT MAX-L exchange. In addition to these, it also gives
six (6) 8MHz (single ended TTL, 75 ohms) clock output along with accompanying
8KHz sync signals (differential TTL) to be used with C-DOT SBM exchanges.
A unique feature of NSE is that in duplex mode of operation, each copy of NSE
supplies half the numbers of output clocks described above and in simplex
operation, the only copy supplies all the output clocks required. This is achieved by
shorting individual card outputs on the motherboard and selecting outputs via
relays. This feature also enables synchronization of exchanges that require
duplicated input clocks as reference clocks.
2.4.
CHECK INPUTS
The NSE can monitor or check clock outputs of the synchronized (target) exchanges
to verify whether they are in synchronisation with the network clock. It can take in
three (3) digital trunks (G.703/6) 120Ω and 3 G703/10, 120Ω clocks supplied from
the target exchanges for monitoring. The digital trunks are connected to the NSE in
non-regenerative mode, i.e., the clock and data information is tapped from the
trunks using high impedance terminations. This results in no disturbance in the
trunks at the destination exchanges where the trunks are terminated with their
characteristic impedance.
2.5.
USER INTERFACE PANEL
NSE has a user-friendly display panel and keyboard arrangement. The display
panel shows the status of various functional blocks of NSE via a set of different
colored LEDs, Alarms are audio-visually indicated, i.e., a beeper accompanies the
LED indications. The keyboard is used for manual operations. Remoting of NSE
alarms is also possible through an opto-coupled interface. A VT-220 emulation is
supported for this purpose. Please refer to Chapter 4 of "C-DOT NSE General
Description" document for more details on the NSE user interface.
2.6.
NSE TERMINAL INTERFACE
Two RS232 Interface are available for each NSE copy as shown in Fig. 2.2. For
debugging purpose a terminal may be connected to NSE as shown in Fig 2.4.
INSTALLATION AND USER MANUAL
PRODUCT DESCRIPTION
11
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