jw@pan.UUCP (Jamie Watson) (05/05/88)
Some time ago I posted a question here about using a PC internal modem in an RT with AIX. The problem was that the first character from each string sent to the modem was lost. Through the efforts of the IBM software support person in Zuerich, I found that the problem was that the UART used in most modem cards, the NS8250, is too slow for the AIX serial device driver. There is a faster version of that UART, the NS16450, which is pin compatible with the 8250. Some of the modem manufacturers are using the newer chip in their modems now - Hayes, I know for sure, and probably others. However, the new modems are not yet available in Europe, and it may be some time (if ever) before the various PTTs approve them. There is hope, though. Because the 16450 is pin compatible with the 8250, those who have (or can get) a modem with the older chip can simply buy a new chip from the local National Semiconductor distributor, and change it themselves. I've done it on a MultiTech PC3 (it's being used to send out this message), and the IBM person has done it on a genuine Hayes. jw