Sorry for "invade" this discussion, but seem the only one about the fluke ir interface for older meters using irda protocol.
Trying to made it simple (and not use an arduino to do the ir encoding/decoding), i've bought an old USB-IRDA adapter model MI620 of the winxp era, as per photo.
Inside i've found an PL2303HX (usb to 232), an eeprom(containing customizations for the 2303), and a chip labeled HS153SN (that i think is a custom mcu for encode/decode the irda protocol) .
As was impossible fo find the drivers for windows 10, i've removed the eeprom (that contained the customized VEN/PID), so now it's recognized as a normal PL2303 device, and i've installed the drivers.
But the meter was not seen by the software. So i've attached the logic analyzer, and sending characters with a terminal with no flow control i had the output to the photodiode, but with flukeview sending the 0x73 0x68 0x13 command i not had any output to the photodiode. I think that flukeview try to use some sort of flow control the my setup can't use (maybe because not using the correct drivers for the module). So i've removed the pins of flow control from 2303 to the HS153SN encoder and now i have a good signal to the photodiode (as seen the logic analyzer output). If i put a glass in front of the transceiver i get back the signal so i think that must work. But flukeview still not see the meter.
The photodiode pulses are encoded correctly (1,62us pulses, as per irda standard) but i not get back anything from the meter at the output of the phototransistor. If while flukeview is sending the data, i put an old phone sending irda data, i have correct signal at the output of the receiver, so or the meter is not understanding the irda code, or it simply not answer. My meter is a fluke 87-IV firmware 1.01. Maybe on that firmware the irda port is not enabled, and is only for the 89-IV?