Still not working.
IBM PCjr computer w/ V20 CPU
512K RAM (64+64+384)
PCjr keyboard (wired)
Racore Drive Two Enhancement Package
Xircom PE3-10BT Ethernet adapter
Straight through Ethernet cable
2Wire ADSL+ modem/router
mTCP tools, April 26, 2009 version
There are no other TSR or device driver loaded in memory.
The only parallel port in this setup is the one provided by the Drive Two sidecar. MSD says it uses port 0378h and IRQ 7. I modified this parallel port to be bidirectional. I am confident that my mod is OK, though it is not yet fully tested. Actually, I thought using the PE3-10BT would a good way to test it... INTERLNK still works fine with the modified port, though I think it only uses nibble-mode transfers by design. PE3PD reports that the adapter will be using the bidirectional mode (unless I use the NON switch).
The status LED turns green when I connect the PE3-10BT to one particular adapter installed in my XP machine using a crossover cable. When connected to any other adapter, hub or router that I own, using a straight through cable, it remains orange most of the time, but it blinks green maybe twice a second. This is strange; I thought this LED should turn and remain green whenever a link is established. When connected to a hub, a LED on the hub indicates that a 10Mbps connection is established.
I tried software interrupts 0x60, 0x61, and 0x70, with and without a hardware interrupt. I also tried to force non-bidirectional mode. I used the script that wipes out the four bytes at 0000:0184. No luck. The packet driver never displays any error messages, except when I forget to plug the adapter in.
I also tried the adapter and mTCP with a modern PC (Pentium III). This machine has Windows 98 SE installed, but I booted it into DOS mode (i.e. DOS 7.1). I tried software interrupt 0x61, with and without a hardware interrupt. No luck. So it seems that the problem is not related to the PCjr, its parallel port, or JRCONFIG. I think that leaves four possibilities: the adapter, the DHCP server, DOS (I only used 6.22 and 7.1), or mTCP (I only used the April 26, 2009 version).
Using either the PCjr or the PC, I noticed I can "see" the DHCP client send its first packet: one of the adapter's two LEDs blinks when I hit the ENTER key. However, the adapter or the software doesn't seem to receive any incoming packets, and it times out after a few seconds. By the way, I only used the modem/router in this series of tests, and it *never* worked, not a single time.
Maybe the adapter is defective. I'd like to rule out this possibility. How could I test it using something else than mTCP? Something small and simple. Any ideas?
I think I will conduct further testing on the modern PC, because it is much simpler for me to do so.
Thanks a lot,