Doubtful, some quick googling seems to indicate that the micromodem iie is a 300bps modem (vs the micromodem II, for which the manual pops up right away). Even if its 1200 or 2400bps, its still likely way to slow to be affected by the codec issues/etc that others have pointed out. You have to remember people are still running fax and home security systems with modems in 2020, so the vast majority of VOIP codecs handle that just fine.
About 10 years ago, I went on a modem kick and wrote a software modem, as well as setting one up at work on a real POTs line to dial in from my house using an old external 56k modem I had lying about. IIRC it linked up at 33.6 without a problem even with a VOIP box on my side (I did tweak the codec at one point, but the default with my provider was already reasonable for modems).
So, its true your not going to get "modern" (56k+) modem speeds on a lot of lines, but even when modems were popular not getting full speed was a continual problem due to line quality issues. So most modems would fall back until they got a reasonable lock. I'm not sure but in the early 2000's there was a state regulatory mandate that POTs lines needed to be capable of 19.2 (IIRC). It wouldn't surprise me if that still exists, even over digital lines to assure that said fax, home security, etc systems continue to work.
Anyway, the point being that at 300bps, your more likely to have problems with the endpoint refusing such a slow connection than having line quality issues.
I had to run my modem at 300bps on my Apple IIe because the built-in serial terminal was "too slow" (scrolling up one line took so long that the buffer would overflow and the beginning of each line would be missing). I ended up talking to the Proterm developer at AppleCon and he said he solved it by using buffers and interrupts, which I knew nothing about.
About 10 years ago, I went on a modem kick and wrote a software modem, as well as setting one up at work on a real POTs line to dial in from my house using an old external 56k modem I had lying about. IIRC it linked up at 33.6 without a problem even with a VOIP box on my side (I did tweak the codec at one point, but the default with my provider was already reasonable for modems).
So, its true your not going to get "modern" (56k+) modem speeds on a lot of lines, but even when modems were popular not getting full speed was a continual problem due to line quality issues. So most modems would fall back until they got a reasonable lock. I'm not sure but in the early 2000's there was a state regulatory mandate that POTs lines needed to be capable of 19.2 (IIRC). It wouldn't surprise me if that still exists, even over digital lines to assure that said fax, home security, etc systems continue to work.
Anyway, the point being that at 300bps, your more likely to have problems with the endpoint refusing such a slow connection than having line quality issues.