How to turn off automatically send NOP command

I connected to a host computer via telnet protocol,this host response NOP command, leading to display some garbled on xshell. I want to turn off automatically send NOP command, but do not know how to set up, can you tell me how to turn off automatically send NOP command feature?

我在学习过程中使用xshell通过telnet协议连接一台主机，由于该主机telnet服务并不规范，响应了xshell定时发送的NOP命令，导致每隔一段时间xshell就会显示一个乱码。我想关掉xshell的发送的NOP命令功能，却不知没有找到设置方法，请问xshell是否支持该项设置，非常感谢。

Program Ver. : Xshell 4