Ser2net终端输出重复行问题求助

我刚接触Linux不久，最近折腾了个基于树莓派4的控制台服务器，用来连接我的思科设备。已经装上了ser2net，功能基本能用，但遇到个头疼的问题：用telnet连接设备后，终端里会重复显示命令提示符，就像这样：

Sw1>
Sw1>

按回车之后还是会重复出现：

Sw1>
Sw1>

我已经折腾两天了，试了各种办法，搜了好多解决方案，现在有点懵，急需大佬们给点建议。

我已经尝试过的操作：

• 换了Putty和Teraterm两款终端工具，调整过各种终端设置，比如CF、LF、强制回显这些选项都试过了
• 更换过USB转串口适配器，排除了硬件的问题，所以应该是树莓派、Linux或者ser2net配置的问题，但我找不到症结所在

下面是我的ser2net配置文件内容，希望能帮大家定位问题：

define: &banner \r\nser2net port \p device \d [\B] (Debian GNU/Linux)\r\n\r\n

admin:
accepter: tcp,8000

connection: &1
accepter: tcp,8001
enable: on
options:
max-connections: 4
connector: serialdev,
/dev/serial/by-id/usb-FTDI_FT4232H_Device_FT78IUDK-if00-port0,
9600n81,local

connection: &2
accepter: tcp,8002
enable: on
options:
max-connections: 4
connector: serialdev,
/dev/serial/by-id/usb-FTDI_FT4232H_Device_FT78IUDK-if01-port0,
9600n81,local

connection: &3
accepter: tcp,8003
enable: on
options:
max-connections: 4
connector: serialdev,
/dev/serial/by-id/usb-FTDI_FT4232H_Device_FT78IUDK-if02-port0,
9600n81,local

connection: &4
accepter: tcp,8004
enable: on
options:
max-connections: 4
connector: serialdev,
/dev/serial/by-idh/usb-FTDI_FT4232H_Device_FT78IUDK-if03-port0,
9600n81,local

connection: &5
accepter: tcp,8004
enable: on
options:
max-connections: 4
connector: serialdev,
/dev/serial/by-id/usb-FTDI_FT4232H_Device_FT78IUTQ-if00-port0,
9600n81,local

connection: &6
accepter: tcp,8004
enable: on
options:
max-connections: 4
connector: serialdev,
/dev/serial/by-id/usb-FTDI_FT4232H_Device_FT78IUTQ-if01-port0,
9600n81,local

connection: &7
accepter: tcp,8004
enable: on
options:
max-connections: 4
connector: serialdev,
/dev/serial/by-id/usb-FTDI_FT4232H_Device_FT78IUTQ-if02-port0,
9600n81,local

connection: &8
accepter: tcp,8004
enable: on
options:
max-connections: 4
connector: serialdev,
/dev/serial/by-id/usb-FTDI_FT4232H_Device_FT78IUTQ-if03-port0,
9600n81,local

connection: &9
accepter: tcp,8004
enable: on
options:
max-connections: 4
connector: serialdev,
/dev/serial/by-id/usb-FTDI_FT4232H_Device_FT78J9GN-if00-port0,
9600n81,local

connection: &10
accepter: tcp,8004
enable: on
options:
max-connections: 4
connector: serialdev,
/dev/serial/by-id/usb-FTDI_FT4232H_Device_FT78J9GN-if01-port0,
9600n81,local

connection: &11
accepter: tcp,8004
enable: on
options:
max-connections: 4
connector: serialdev,
/dev/serial/by-id/usb-FTDI_FT4232H_Device_FT78J9GN-if02-port0,
9600n81,local

connection: &12
accepter: tcp,8004
enable: on
options:
max-connections: 4
connector: serialdev,
/dev/serial/by-id/usb-FTDI_FT4232H_Device_FT78J9GN-if03-port0,
9600n81,local

备注：内容来源于stack exchange，提问作者Tjaa