Selection and Testing of Electronic Components for LM

" The maximum number of lines that can be connected
to a certain switchboard is dependent on a
number of factors, such as the amount of traffic,
type of traffic, the efficiency of the operator, calling
habits, local tradition etc. Under normal circumstances
an operator in a single-position magneto
switchboard can handle a maximum of 100-140
magneto lines and 8 CB lines. However, if the
amount of traffic is very small it is possible in some
cases to handle more than 200 lines
Technical data
Maximum number* of
magneto lines
CB junction lines
Cord pairs
Dimensions in cm
Width
Height
Depth
Approx. weight, kg
Operating voltage
6VD.C.
Base unit
+ 1 line box
80 70 60
- 4 8
18 18 18
62
41
53
40
Line resistance
The maximum value of the line resistance
for magneto lines is dependent on
the line attenuation, which may amount
to 15 dB. The leakage resistance must
not be less than 10000 ohms. The indicators
drop at 9 mA. The resistance and
leakage values for CB junction lines are
primarily dependent on the limit values
of the main exchange. Thus the maximum
values for these lines must be
calculated on the basis of data from the
main exchange.
Base unit
+ 2 line boxes
160 150 140
- 4 8
18 18 18
ABJ 101
62
59
53
55
Base unit
+ 3 line boxes
240 230 220
4 8
18 18 18
62
77
53
70
Advantages
The exchange has been given all the
characteristics that can be demanded
from a modern manual magneto
switchboard which means that
— CB junction lines from manual or automatic
exchanges can be connected
— magneto junction lines can be connected
to the ordinary magneto units
— supervision of a junction line can be
carried out by the operator while
handling other calls
— line splitting gives the operator the
possibility of talking to one party
without the other being able to overhear
the conversation
— the ringing is generated automatically
(transistorized)
— a flag indicator indicates that a signal
is being sent out
— a ring-back tone is sent to the caller
— backward ringing can be carried out
via the answering cord
— acoustic signals can be obtained
concurrently with incoming seizure
and clear-forward signals
— a fixed acoustic signal can be connected
in by means of a switch
— dropped indicators are automatically
reset during the handling of the calls
— a battery indicator indicates when it
is time to check the condition of the
battery
— testing of the cords can be performed
— an automatic fuse eliminates fuse
changes
— anextrajack is provided for connecting
in a handset for an assistance
operator
— space is provided forthe memoranda
that the operator needs to have readily
accessible in order to be able to
work rapidly and efficiently.