A friend wrote me, and it was so amusing I'm posting it here. To all of us with Serial Ports skills, read on:
Some months ago I upgraded my home PC from XP to Windows 7 x64 which was surprisingly uneventful. Everything “just worked” and I quickly overcame my initial apprehension - all the concerns about apps failing to work (or having to run in XP mode) never materialised. However, one piece of hardware did not work under Windows 7 (it barely ran under XP because it was so old) and this was an old Quatech 8-port USB-to-Serial converter which I used to connect to the console ports of my Cisco lab equipment. (Quatech are still going, since 1983, but just not providing new drivers for obsolete equipment…) I really wanted an Ethernet-to-Serial converter (what used to be called a “terminal server” in the old days) but the price was prohibitive, with even old units on eBay retailing for £500 upwards. Today, it’s still the same, these old crappy terminal servers still retail for stupid prices. But I needed one and there was simply no way to get the old Quatech unit working – the new requirement was to run in Windows 7 x64 and they stopped making drivers for it years ago.
While browsing eBay recently I came across exactly what I wanted for only £50, so I promptly used “buy it now” and, via the wife’s parents, got it shipped over to
What I should have done, of course, is checked the availability of Windows 7 x64 drivers before purchase (among other things, more later) but I was excited to finally get my hands on a proper terminal server and anyway, how hard could it be? Back when I was a VAX/VMS programmer I don’t recall having to install drivers to get a terminal server working, that’s why we had LAT! (I know, there’s a wee bit of difference between a VT220 and a PC ;-)
So, unwrapping the shiny new (well, dull and old, to be honest) terminal server from Equinox (who?) a first glance confirms that it looks like just what I need. One 10/100 Ethernet port and 8 RJ45 serial ports. Perfect. OK, power it on. OMG! Where’s my ear defenders? How can this little box make this much racket? Never mind, some green LED’s light up and start flickering which looks like a good sign. I connect it to the network and go looking for a Cisco rollover cable. An hour later I stop looking for a rollover cable. I actually have dozens of these, not only the eight from the Quatech box, but they are all RJ45-to-DB9 terminated, whereas I need a RJ45-to-RJ45 rollover.
Anyway, that’s for later, first I need to connect to the box. Before I do that I span the Equinox switch port to a laptop running Wireshark – I just know I’ll be needing that at some point. So, what’s the default IP for the box? Hmm. Now I’ll need the manual. So, it turns out that Avocent bought Equinox way back in 2001 but they’ve done an excellent job of keeping the old docs available, and not only that – drivers!
Apparently the default IP is 18.104.22.168 (no subnet mask given) so I renumber another laptop’s IP to 22.214.171.124/24 and try pinging 126.96.36.199. Nothing. I try /8 and /16 subnet masks just in case (you never know, and it was quicker that enabling proxy-arp on the router), then try pinging the subnet broadcast, and anything else I can think of. Still nothing. I make a static arp entry for 188.8.131.52 and try again. Wireshark shows packets in, but nothing coming out. I go back to the manual and look for the flash reset, just in case it’s still got an old IP. Yes, I should have done this first... Anyway the reset works, but still nothing. On a hunch, I reset while connected to the LAN and voila! A DHCP request! A bit more testing shows that this only happens on a hard flash reset. My DHCP is more secure that it probably needs to be (I only allocate enough IP’s for the devices I have and no more, among other brain-dead ideas) so a quick reconfiguration and the Equinox has an IP. I can ping it, but a quick check to see if it’s got a web interface (it doesn’t) confirms I need to get some drivers.
The latest drivers include
Now I need that bloody cable. I have literally hundreds of cables, serial cables, USB cables, Ethernet cables (all kinds, cross-over, straight, custom..), scsi cables, fibre cables, two whole boxes of video cables – so anyway it takes me another couple of hours to realise that I don’t have any RJ45-RJ45 rollover cables. Another hour messing about with DB9 and DB25 adapters. No joy. However, I won’t let something like that stop me so I’ll just make one!
So, I have the crimp tool but I’m out of plugs. As I’m now getting desperate, as well as more and more inebriated, having finished the beer and started on red wine, I cut an Ethernet cable in two, strip it down to the bare wires and make a rollover. The flashing lights on the cheap cable tester I have confuse me, so I manually check the pinouts with multimeter probes. Not such a wise move given my current state as the probes have very pointy ends. I clean up and apply a bandage.
Everything is now done. The box is up and running, COM ports are installed (with nice configuration panel for each port) and I’m fully cabled. I configure port 1 for 9600, 8N1 no flow control and fire up putty. Putty also needs serial port parameters, so I input those, select COM11 (which I’m assured is port 1 on the Equinox) and press
Deep breath. Sip of wine. Relax.
Keyboard says no.
Start again. Check Wireshark – I have a nice trace file, but no decode. Slightly unusual not to have a Wireshark decode, but maybe the protocol is proprietary. However, I don’t think that’s the issue – whenever there are problems with serial connections it’s always a safe bet that it’s the cabling. (I try all the other RJ45 terminated cables I own, mostly Ethernet, just in case some random wiring shows me some luck but none of them work.)
The Avocent site shows an app called “Connections Manager” alongside the drivers (or “administration utilities” – what’s wrong with calling it a bloody driver?)
The connections manager program won’t install on Windows 7 so I try XP on a laptop. It needs the
driver administration utility installed first. However, I eventually get it installed. This turns out to be an amazing program! Complete monitoring of serial traffic in and out, including pin utilisation, and a full datascope. I check local loop first. Works fine, so nothing wrong with the box. External loop doesn’t work. Well, duh! Obviously it doesn’t or I wouldn’t be here.
Back to the manual – what’s the pinout for the serial ports? O my f** god! It has 10 pins!!! How can a f**** RJ45 plug have 10 pins!! I calm down and count the number of pins in port 2. It has 8. OK, why does the manual say 10? The picture is the same, the model number is the same – wait, it isn’t - this manual is for an ESP-8 MI and I have vanilla ESP-8. OK, I dig around and find the correct manual. At first glance it looks identical, but the pinouts have 8 pins not 10. Whew.
I examine the pins, and find that they are not the same as the Cisco pinouts. Apparently, there is no standard for RJ45 serial port pinouts. So, what do we need? A rollover is no good. We don’t need DTR/DSR or RTS/CTS as Cisco console ports don’t support hardware flow control. Ditch DCD also. What’s left? RxD and TxD pins and ground. Should be enough, so I perform some more bare wire surgery and tape up the patient.
Keyboard say no.
What IS the problem? Datascope shows TxD active for every
More cable surgery...
Yaaaaaayyyyy!!!!! At last!!!
I really shouldn’t have put those probes down there. And that’s the lesson. Be careful where you put your probes.