Noise Sources
Avoid locating near
suspected interference sources such as: Lamp dimmers, Fluorescent lamps,
Electronic igniters, CRT monitors, Battery chargers, Switching power
supplies, Motors, Automobile ignition systems, Power lines, Nearby Cell
transmitters Note: Interference is diminished by the square of the distance (i.e.,
doubling the distance from the source will reduce its effect by 4).
Broadcast Reception
In some areas of the country the CDMA service may
not be available. Check to see if Sprint or Verizon has cell
phone service in the area.
Data
Cabling
The recommended
cable type is RS-232.
Serial Cable Length Limits
(RS-232)
Table below lists the maximum permissible cable lengths
for various protocols at various representative data rates. These lengths
are as specified in the EIA RS232C, CCITT V.55 and RS422 interface
standards.
Material requirements:
-
Conductor
size and type: 24 AWG, twisted pair.
-
Nominal
capacitance: 15.5 picofarads per foot (between
conductors of each pair); 27.5 picofarads per foot (from each conductor to
shield).
-
Nominal
DC resistance (each conductor): 24.0 ohms per 1000 feet.
-
Nominal
DC resistance (shield): 2.35 ohms per 1000 feet.
-
Shield
type: Overall braided with drain wire.
Note on RS-232 Serial Cables:
At
lower peripheral speeds of up to 9600 baud, serial interfaces can usually operate over cables up to 100 feet
long. Use of special high quality cable may in some cases allow this limit
to be extended to as much as 200 feet.
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