11/98 6-1 U3-1050
Westinghouse Proprietary Class 2C
Section 6. Modem Support
6-1. Section Overview
This section describes the modem support of the Link Controller Modbus interface.
The LC/Modbus interface can be used in conjunction with a Hayes compatible
telephone modem to perform Modbus communication over the public switched
network. The interface uses the RS232 handshaking lines to control the connection.
Configure the modem with the following settings:
• To hang up and go to command mode on (on -> off) transition of DTR.
• To dial on (off -> on) transition of DTR from cell 0
• To have an appropriate telephone number in cell 0
• Carrier detect follows received carrier
During operation, the interface program will check the state of the Carrier Detect
handshake line before execution of each point group. If no carrier is detected, the
interface signals to the modem that it should attempt to reconnect by dropping and
raising the Data Terminal Ready handshake line. The interface then waits for
successful connection before continuing with the point group. Once the connection
is made, the interface flushes any spurious characters in the buffer and proceeds.
Several /FILE attributes control the operation of the modem support routines. Set

1998年11月6-1 U3-1050
西屋专有2C级
第六节。调制解调器支持
6-1. 章节概述
本节介绍链路控制器Modbus接口的调制解调器支持。
LC/Modbus接口可与Hayes兼容的
通过公共交换网络进行Modbus通信的电话调制解调器
网络该接口使用RS232握手线来控制连接。
使用以下设置配置调制解调器：
•挂断并进入DTR转换的命令模式（开->关）。
•从小区0拨开（关->开）DTR转换
•在小区0中有一个合适的电话号码
•载波检测跟踪接收到的载波
在操作过程中，接口程序将检查载波检测的状态
在执行每个点组之前握手。如果未检测到载波，则
接口向调制解调器发出信号，表示调制解调器应通过断开和断开的方式尝试重新连接
提升数据终端就绪握手线。然后，接口等待
在继续使用point group之前成功连接。一旦连接
创建后，接口刷新缓冲区中的所有虚假字符并继续。
几个/FILE属性控制调制解调器支持例程的操作。设置