Section 6. Troubleshooting
6-3
6.3 Communication Options
HARD WIRED DIRECT CONNECT SHORT HAUL MODEM
— The
RAD SRM-5A short haul modem plugs into the SC932C. There is a short
cable that runs from out the back of the RAD to the terminal blocks in the
middle of the enclosure. A ribbon cable runs between one side of the SC932C
and the 9-pin plug marked “CS I/O”. The RAD modem and SC932C get their
power through the ribbon cable from the datalogger. Both devices run off of 5
VDC that comes from pin 1 on the 9-pin plug. Ground is pin 2.
The SC932C is NOT a simple 9 to 25 pin adapter plug.
It contains active circuitry and must be replaced by an
identical device or damage will occur to the RAD
modem and the protective circuitry. The SC932C
replaces the older SC932. The devices are
interchangeable.
The 9-pin plug marked “CS I/O” is NOT an RS232 port and
cannot be plugged directly into a laptop.
PHONE MODEM
— The COM200 phone modem is a specially made data
modem that runs off of DC voltage. The modem plugs directly into the RJ-11
jack inside the enclosure for phone line access. A ribbon cable runs between
the COM200 and the 9-pin plug marked “CS I/O”. The COM200 requires two
power supplies to operate. It requires 12 VDC from pin 8 of the 9-pin plug as
well as 5 VDC from pin 1 of the same plug. Ground is pin 2. If either supply
should fail, the modem will not work.
6.4 What’s at the Computer
HARD WIRED DIRECT CONNECT SHORT HAUL MODEM
— A RAD
SRM-5A short haul modem plugs into one of the serial COM ports at the
computer. Between the RAD modem and the incoming communication cable
from the weather station should be a box marked “JOSLYN”. This box
contains surge protection for the communication cable. Inside this box are four
posts that have a center “foot” that should be going to a good earth ground. If
the spark gaps are not properly grounded, then there is no protection.
PHONE MODEM
— An internal or external phone modem is required at the
computer to call up a phone modem station. It’s a good idea to have computer
grade surge protection on AC power going to the computer, modem, printer,
and monitor. Also get surge protection for the phone line coming into the
computer’s modem.
WARNING
NOTE
