with the default Log time of 12 minutes (1 minute per division).
To begin the Log measurement, follow the procedure detailed
in the Traffic Mode section for attaching the instrument to the
cable, ensure that “LOCK" appears next to the elapsed time
display and press
Enter
. The Net-Advisor immediately begins
to build a histogram of the traffic levels.
The Log bar
graphs display the
average traffic
(“AV” bar graph in
the Traffic Mode)
and are scaled to
the currently selected maximum range with a default value of
10%. The bar graphs are updated with every one second
measurement until time for the division is complete. When a
division is complete, the bar graph for the current division is
frozen and the instrument begins displaying the bar graph for
the next division. The Net-Advisor freezes the data by
automatically setting “HOLD” when all the divisions are complete.
Pressing Log will also create the “HOLD” condition. Pressing
Log after “HOLD” appears will clear the display and reset the
Net-Advisor for another Log measurement. All other buttons
(except “ON”) are active only when the Log Mode is in this reset
state.
The Net-Advisor can be left running even after the Log time
has been completed without affecting the recorded data. For
Log durations of three hours or more, it is recommended that
the AC Adapter is used.
CONTROL SETTINGS
CONTROL SETTINGS
CONTROL SETTINGS
CONTROL SETTINGS
CONTROL SETTINGS
Audio/LED Contr
Audio/LED Contr
Audio/LED Contr
Audio/LED Contr
Audio/LED Control
ol
ol
ol
ol
From the Traffic screen
(in initial or reset state),
Audio or LED settings are
entered by pressing the
corresponding button. Once
in Audio or LED the settings
change when the scroll
button is pressed. Press
Enter to exit the screen.
I N T R O D U C T I O N
Theory of Operation
Computer networks communicate by transmitting
and receiving information in the form of digital
signals. This information is electrically represented
by pulses of energy transmitted by a physical media
which is typically a metallic cable. Each pulse
travelling along a metallic cable creates an
electromagnetic field around the cable proportional
to the amplitude or strength of the pulse. These
radiated or “leaked” signals are sometimes referred
to as Electromagnetic Interference or EMI. Modern
cables use different techniques to reduce the amount
of leakage such as shielding or field cancellation by
tightly twisting the wires together. These techniques
dramatically reduce but can not eliminate the signal
leakage through the cable.
The Net-Advisor is an ultra-sensitive receiver tuned
to the different network frequencies that is able to
detect and measure the leaked signals from the
digital bits of data that are travelling through the
cable. The Net-Advisor makes continuous
measurements of these network signals which are
displayed and updated once per second. The
measured data is displayed as a percentage of total
bandwidth. For example, on an Ethernet system
(10baseT, 2 or 5) the maximum bandwidth is 10
million bits per second (Mbps). If during a one
second measurement, the Net-Advisor detects one
million data bits the display will show a reading of
10% utilization. The various features provided by
the Net-Advisor are based on this continuous
detection, measurement and display of the leaked
data bits.
The Net-Advisor reads all of the traffic on a
segment or dedicated port. It does not filter for traffic
on a single node or address. Traffic can be monitored
from any point on a network that is not isolated from
the rest of the network.
OPERA
OPERA
OPERA
OPERA
OPERATING MODES
TING MODES
TING MODES
TING MODES
TING MODES
Press
ON
to activate the Net-Advisor. When the unit is turned
on it presents a Net-Advisor start up screen for 2.5 seconds and
automatically transitions to the Traffic screen which is the master
screen that is returned to from all other functions.
TRAFFIC
TRAFFIC
TRAFFIC
TRAFFIC
TRAFFIC
The Traffic Mode
starts with the
default conditions of
10 Mbps Ethernet
running on UTP
cable (10baseT). If
the network to be tested is another configuration, go to the Setup
screen to select the appropriate parameters (see Control
Settings). To begin taking measurements push forward the
Slide
Button
on the right hand side of the instrument to open the
cableport, place the selected cable in the port and release the
slide button to close.
The Net-Advisor
immediately begins
to sense for signals
and if any are
present it will display
the word “LOCK”
next to the elapsed time field. This shows that there is adequate
leaked signal to make the measurement. Note: The strength of
the leaked signals varies along the length of the cable. It is
possible to find very small sections of a cable, typically 1 to 2
inches, where leakage is very low and “LOCK” appears
intermittently or not at all. With the cable in the port, slide the
cable a few inches in either direction until “LOCK” appears
consistently or you have confirmed that no signals are present.
Once “LOCK”
appears, press
Enter
to start the
measurement and
display process.
Pressing
Traffic
a
second time stops the process, freezes the recorded data and
presents the word “HOLD” in the display. Pressing
Traffic
again
resets the Net-Advisor to make another traffic reading. All other
buttons (except "ON") are active only when the Traffic Mode is
in this reset state.
Collision Index (CI ) - Is based on the calculated probability
of collisions occurring on the segment being tested. This
probability applies to Ethernet shared segments with "1"
indicating a very low probability and "5" indicating a very high
probability of collisions occurring. CI is calculated from Average
Traffic and continuous readings of "4" or "5" indicate system
upgrade should be considered. An arrowhead displayed in this
field means that a higher Max Range should be used.
T
T
T
T
Trrrrraf
af
af
af
affffffic bar g
ic bar g
ic bar g
ic bar g
ic bar grrrrra
aa
a
aphs:
phs:
phs:
phs:
phs:
IN - Instantaneous display of the network traffic
for the previous one second.
AV - The average of all the one second traffic
measurements since Enter was pressed.
PK - The peak traffic level recorded in any one
second measurement period.
Note: When the Net-Advisor is first powered on, the full scale
default setting is 10%. The 10% setting gives a full scale dis-
play of 1 Mbps for Ethernet. The Net-Advisor is configured in
this manner because Ethernet network traffic levels are typi-
cally below 50% and this setting improves display resolution of
the bar graphs in the Traffic Screen. To set full scale to any
other value go to the Setup Screen and make the selection -
see Setup below.
A Digital display for-
mat for Traffic is se-
lected in Setup
through the Max
Range field by
choosing "DD%".
L
LL
L
LOG
OG
OG
OG
OG
The Log Mode records network activity or bandwidth
utilization over time.
Log has seven
settings from 12
minutes to 24 hours
(see Setup below)
LED
LED
LED
LED
LED
LEDs are used
when viewing the
instrument at a
distance. The
Net-Advisor is
designed so that
the LEDs can be viewed even when it is laid flat. LEDs display
the Instantaneous traffic (“IN” bar graph in the Traffic Mode)
with each LED representing 10% of the full scale bandwidth.
A
A
A
A
AUDIO
UDIO
UDIO
UDIO
UDIO
Audio is used
to alert the user
when network
utilization has
exceeded the
selected level.
The Audio tone is tied to the Instantaneous traffic (“IN” bar graph
in the Traffic Mode) and is generated once during each one
second measurement if the threshold level has been exceeded.
Audio has 11 threshold settings beginning with “On” and
increasing in 10% increments to 100%. The default setting is
“On” which will cause the tone to be generated when traffic is
detected during the measurement period.
SETUP
SETUP
SETUP
SETUP
SETUP
Setup has six
selectable fields
with the active
field being
indicated by the
arrowhead in
the center column of the screen.
Network Type. When entering the Setup screen, the first field
shows that the Net-Advisor is for use with Ethernet (10BaseT) .
Cable Type. The default setting for Cable Type is Unshielded
Twisted Pair (Category 3, 4 or 5) and is indicated by the reversed
out “UTP”. Press
Scroll
to advance to “STP” (Shielded Twisted
Pair) and then “COAX” for coaxial/thinnet/10base2 cables.
B
B
B
B
BA
A
A
A
ATTER
TTER
TTER
TTER
TTERY
Y
Y
Y
Y
The Net-Advisor operates on two AA size batteries. To remove
the battery cover located at the bottom of the unit, press down
on the battery cover end with dimples with the right thumb. This
relieves the pressure on the battery cover latches. While pressing
down with the right thumb, slide
the cover horizontally (away
from your body). The cover will
move approximately one
quarter of an inch and separate
from the unit.
Add or replace batteries as
shown. Check that the cover
orientation is correct by
ensuring that the AC adapter
hole in the cover is aligned with
the adapter jack pin inside the
Net-Advisor.
BO
BO
BO
BO
BOX CONTENTS
X CONTENTS
X CONTENTS
X CONTENTS
X CONTENTS
Net-Advisor
Basic RS
Data Clamp
1 1
AC Adaptor
1 1
Carrying Case
1 1
User's Guide
1 1
RS-232 Cable
1
Sotware Diskettes
2
AA Alkaline Batteries 2 2