On that day the MTR of RS-232C is not more than 115.2kbps(on 16550 compatible chip) and was slower than 128kbps of 2B-ISDN bulk trafic. Many PC magazines reported about this, and I got this I/F card....I guess.
But the desktop PC hardware enviroment is stable and I was afraid that it became unstable if I installed this device....so I hesitated to use this and the day to change to ISDN came at last.
I connect the original RS-232C port to TA.....Oh, It can connect.
Certainly MTR of subscribe is ap. 8Kbytes/sec in 64kbps mode and ap.11kbytes/sec in 2B bulk mode, so the max headroom was there. But I was pleased and satisfied to upgrade from the MTR 4kbytes/sec of analog modem, so I have no coullage of trying this card....
It's also "junk that's never used".