Neptune Technology TRICON SmartTrol, Руководство по установке и обслуживанию

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TRICON
®
SmartTrol
™
Installation and Maintenance Guide
39
Chapter 11: RS-232C Serial Communication Operations
The RS-232C communications port obtains information from the SmartTrol™ by a host
computer. RS-232 is an EIA (Electrical Industry Association) specification for the electrical
characteristics and signal assignments for a serial communication format. The SmartTrol
expects the connection to the host computer to comply with the electrical characteristics
for RS-232C.
PIN Assignments
The SmartTrol operates as Data Communications Equipment (DCE) and has connection
pin assignments as shown in the table.
Connector Pin # Signal Name Description
2 RD RECEIVED DATA (from host).
3 TD TRANSMITTED DATA (to host).
4 RTS REQUEST TO SEND (from host).
5 CTS CLEAR TO SEND (from SmartTrol).
6 DSR DATA SET READY (from SmartTrol).
7 GND SIGNAL GROUND.
8 RSLD RECEIVED SIGNAL DETECT.
20 DTR DATA TERMINAL READY (from host).
Table 16 – Pin Assignments
The SmartTrol only requires the TD, RD, and GND pins for normal operation. No control
signals are controlled by the normal operation. No control signals are controlled by the
SmartTrol for access control (handshaking). To enable most host devices to operate with
the SmartTrol, the RTS, and CTS lines are tied together in the SmartTrol. Also, DSR is
internally connected to DTR and RSLD to give proper signal levels to the host computer.
Communication between the SmartTrol and the host computer must be seven-bit ASCII
code. The code is embedded in a serial word that has a parity bit, start bit, and stop bit.
(Having eight data bits with no parity bit would be the same as seven data bits with parity
selected to be a space). The total number of bits then is 10 bits per character.