Windows 在第一个命令仍从批处理文件运行时启动第二个命令

我正在尝试创建一个批处理文件，该文件将运行一个实用程序，该实用程序打开与internet上设备的连接，然后启动telnet会话。一旦连接打开，批处理文件就无法继续

批处理文件

@echo off  
set /p serial=What are the last 8 of the STB's serial?   

udp.exe -c 127.0.0.1 23 %serial% x.x.x.x 11111 127.0.0.1 23 | telnet 127.0.0.1

输出

What are the last 8 of the STB's serial? XXXXXXX  
Ready for XXXXXXX

它只是处于“就绪…”行，从不打开telnet连接。我试过各种各样的|和&但是运气不好。

启动/B有帮助吗

开始？给予

Starts a separate window to run a specified program or command.

START ["title"] [/Dpath] [/I] [/MIN] [/MAX] [/SEPARATE | /SHARED]
      [/LOW | /NORMAL | /HIGH | /REALTIME | /ABOVENORMAL | /BELOWNORMAL]
      [/WAIT] [/B] [command/program]
      [parameters]

    "title"     Title to display in  window title bar.
    path        Starting directory
    B           Start application without creating a new window. The
                application has ^C handling ignored. Unless the application
                enables ^C processing, ^Break is the only way to interrupt
                the application
...