Section 6. 9-Pin Serial Input/Output
6-7
State 5
State 5 is a branch from State 1 when the SDE line is high and the CLK/HS line is
low. The SDs must drop the Ring line in this state. This state is not used by SDs.
The CR10X must force the SDs back to the reset state from State 5 before
addressing SDs.
State 6
State 6 is a branch from State 1, like State 5, except the SDE line is low and the
CLK/HS line is high. The SDs must drop the Ring line in this state.
6.6 Modem / Terminal and Computer Requirements
6.6.1 SC32A Interface
Most modem and print peripherals require the SC32A Optically Isolated RS232
Interface. The SC32A raises the CR10X’s Ring line when it receives characters
from a modem, and converts the CR10X’s logic levels (0V logic low, 5V logic
high) to RS232 logic levels.
The SC32A 25-pin port is configured as Data Communications Equipment (DCE)
(see Table 6-3) for direct communication to Data Terminal Equipment (DTE),
which includes most PCs and printers. For connection to DCE devices such as
modems and some computers, the SC932 9-pin to RS232 interface should be used.
When the SC32A receives a character from the terminal/computer (pin 2), 5V is
applied to the datalogger Ring line (pin 3) for one second or until the Modem
Enable line (ME) goes high. The CR10X waits approximately 40 seconds to
receive carriage returns, which it uses to establish baud rate. After the baud rate
has been set the CR10X transmits a carriage return, line feed, and ‘*’, and enters
the Telecommunications Command State (see Section 5). If the carriage returns
are not received within the 40 seconds, the CR10X drops out of telecommunica-
tions.
1.
The SC32A has a jumper which when used, passes data only
when the ME line is high and the SDE line is low. The
function of the jumper is to block data sent to SDs from being
received by a computer/terminal used to initiate data transfer.
Synchronous data will appear as garbage characters on a
computer/terminal.
2.
Please refer to the SC32A manual for pin descriptions and
other technical details.
3.
The SC929 RS232 Interface Cable is suitable for interfacing
between the CR10X and battery-powered (laptop) PCs.
6.6.2 Computer / Terminal Requirements
Computer/terminal peripherals are usually configured as Data Terminal
Equipment (DTE). Pins 4 and 20 are used as handshake lines, which are set high
when the serial port is enabled. Power for the SC32A (or SC929) RS232 section
NOTE
