Power; Voice Signaling; Rbs - Harris CM-30 Installation & Operation Manual

NetXpress LX & CM-30 Installation & Operation Manual
Version 1, September 2010
FEC HIGH (used in more serious packet loss conditions)
Triple error correction is engaged. This scheme introduces a 100% overhead (increased bandwidth
required) and can correct one, two, or three consecutive packet losses. In this scheme, the packet
sequence sent is critical if it is to protect against consecutive packet losses.
Table 2-3 shows the NetXpress LX performance data, with an overall loss rate and a percentage of
high versus low FEC loss.
Table 2-3. NetXpress LX FEC Performance Data
Network High
Loss FEC
Rate Loss
(%) (%)
1 0.0017
2 0.0023
3
4
5 0.0168
6
7
8
9
10 0.14
11
12
13
14
15 0.597
% High FEC Loss ((Lost packets / Rx packets) x 2) x 100
% Low FEC Loss ((Lost packets / Rx packets) x 1.5) x 100

2.9 Power

The NetXpress LX-300 system supports redundant power supplies. You can install a main power
supply and a redundant supply in case the main supply fails. The system runs on either AC or DC
power supplies, and supports 60 W and 100 W AC powered and 50 W DC powered supplies. (Section
3.2.4 – Power Supply Installation gives more information on NetXpress LX power supplies.)

2.10 Voice Signaling

Voice signaling communicates voice channel call progress information over a data link. The
information, known as ABCD bits (or E & M) includes busy, idle, or other ringing state indications to
alert the caller that a call is taking place. Two types of voice signaling are robbed-bit signaling (RBS)
and channel associated signaling (CAS).
2.10.1

RBS

T1 systems use the RBS method of channel signaling. This information is embedded into the least
significant bit of the audio channel once every 6th frame and injected into the channel without regard
to the remaining bits. Therefore, RBS does distort the voice audio signal so slightly that you can only
2-18
Low
FEC
Loss
(%)
0.027
0.085
0.507
2.1
4.87
2 – Functional Design
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