Free Serial Port Monitor allows you to intercept, display and analyze all data exchanged between the Windows application and the serial device. It can be successfully used in application development, device driver or serial hardware development and offers the powerful platform for effective coding, testing and optimization.

Fiddler is a Web Debugging Proxy which logs all HTTP(S) traffic between your computer and the Internet. Fiddler allows you to inspect all HTTP(S) traffic, set breakpoints, and "fiddle" with incoming or outgoing data. Fiddler includes a powerful event-based scripting subsystem, and can be extended using any .NET language.

Fiddler is freeware and can debug traffic from virtually any application, including Internet Explorer, Mozilla Firefox, Opera, and thousands more.

An I thought the Fiddler name was a metaphor for the bow going back an forth like HTTP messages.

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% /home/cs1721/bin/emu /home/cs1721/public_html/05s2/emu/examples/iota.hex
Emu Reference Implementation v0.?
> program
0000: e000 LDI R16,0
0001: e081 LDI R24,1
0002: 2fa0 MOV R26,R16
0003: e7f0 LDI R31,112
0004: e0e0 LDI R30,0
0005: 9509 ICALL
0006: e011 LDI R17,1
0007: 0f01 ADD R16,R17
0008: e614 LDI R17,100
0009: 1b10 SUB R17,R16
000a: f7b1 BRBC 1,-10
000b: e080 LDI R24,0
000c: e7f0 LDI R31,112
000d: e0e0 LDI R30,0
000e: 9509 ICALL
> registers
PC=0000 SP=1100 SR=[C=0,Z=0,N=0,V=0]
r00-r0f 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
r10-r1f 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> step
0000: e000 LDI R16,0
PC=0001 SP=1100 SR=[C=0,Z=0,N=0,V=0]
r00-r0f 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
r10-r1f 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> run
0
1
...
8
9
> restart
> run
0
1
...
9
> registers
PC=000f SP=1100 SR=[C=0,Z=1,N=0,V=0]
r00-r0f 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
r10-r1f 0a 00 00 00 00 00 00 00 00 00 09 00 00 00 00 70