CompuServe Messages

Doug, If you have /FIFO=Y set in the TAP config file and you don't see the tap string about it actually being turned on, chances are you don't have a 16550 serial chip on the comm port. If you have an internal modem the comm port is part of the modem board, but if you have an external modem the comm port is part of the I/O board installed in the 'puter (or on the mo-bo). The only reason it's rather essential to have one of the faster serial port chips is that the 16450 chips that were used in the original ports is only reliable at speeds up to 9600 baud. (that's also the reason most plotters are limited to this comm speed too.) Now there were 16450 chips that would run reliably at speeds above this, but it was only a fluke. The spec on the chip only tests the chip at a maximum speed of 9600. The 16550 chip is tested at a maximum speed of 57,600 baud and should work reliably up to that speed. But to get it to do this, they have added a 16 bit buffer that is called the FIFO buffer. It stands for First In First Out. This gives the chip a little slack and prevents data loss at the higher speeds. But the buffer actually has to be initialized by the comm program that is using the serial port for it to work. The FIFO buffer isn't always active. This is to maintain compatability with programs and hardware that were made for use in the slower ports. The buffer can actually throw these for a loop and time them out. So you gotta initialize the buffer before you can use it. So that's why tap has the /FIFO=Y in the config file. The connect rate is also settable in the TAP config file, and essentially tells your hardware and software what data transfer rate you want between the modem and the serial port. It don't have anything to do with the phone line speed or data transfer rate. If you don't have a FIFO buffer, this munber shouldn't be any higher that 9600 baud. The &K4 enables software flow control. The &Q9 tells my PPI modem to conditionally use v42bis compression rather than MNP/5 (CIS doesn't support MNP/5…or at least they didn't) The S95=44 enables the CARRIER, COMPRESSION and PROTOCOL messages at logon. I've been thinking of changing this to 47 to get the error correction and actual line speed too.