Scientific Software Tools, Inc.
It can be used for the configuration and maintenance of products.
It is also a very handy utility during your LPT port development activities.
It is the missing link between devices that speak UDP on your network.
UDP Test Tool is both a UDP packet generator and listening application.
COM Port Stress Test is a tool for testing a COM or RS232 port (device).
Simple Port Tester is a neat application created to test TCP and UDP ports.
Active Ports monitors all open TCP and UDP ports on a local computer.
Virtual Serial Port Software
Monitor, analyze and save logs from your system's RS232/422/485 serial COM ports.
upRedSun and iForwarder, Inc.
It will let you port forwarding to multiple IP addresses at the same time.
Verigio Communications Inc.
Multi Port Forwarder enables you to redirect requests to another IP and port.
VSPE is intended for engineers and developers to create/debug/test applications.
The dialer uses one local UDP port and one local TCP port.
ServerTalk lets you communicate directly with a TCP or UDP port on a server.
It is an advanced serial port test, simulation and data analysis tool.
PFPortChecker is a useful and reliable port test application.
VirtualCOM-UDP is a software based UDP/COM Port Redirector solution.
NetworkActiv AUTAPF is a UDP and TCP port forwarder.
Serial Port Tool
Professional debug tool for serial port, TCP/IP, UDP, I2C, HTTP communication.
Scriptable data terminal supporting serial port, UDP, TCP client/server, etc.
It generates IP/ICMP/TCP/UDP traffic from clients to stress test servers.
CTLWIN - manage test programs and script files on the R+ and H+ line.