How can I establish a serial connection (aka tip hardwire session) from one Sun machine to another?
A: Depending on which Sun machines you are connecting, you will need a certain type of null modem cable suited to that machine. Most older Sun machines (UltraSPARC II and some III) will require a DB25 male connector on the end. Newer ones (some UltraSPARC III and IV) will need RJ-45 serial connections.
SUMMARY:
1) Decide which machine will be doing the ‘observing’ and which will be the ‘observed.’
2) Connect one end of the cable to serial port B on the ‘observing’ machine and the other end of the cable to serial port A on the ‘observed’ machine.
3) Establish a tip hardwire session.
4) How to send a break, terminate the connection, etc…
DETAILED:
1) Decide which machine will be doing the ‘observing’ and which will be the ‘observed.’
For the purposes of this solution, the machine you will be working from will be called the ‘observing’ machine, and the machine that you are consoled into will be called the ‘observed’ machine. They keyboard should NOT be plugged into the the ‘observed’ machine, as this will send all the output to the video card, instead of allowing it to go to the serial port.
2) Connect one end of the cable to serial port B on the ‘observing’ machine and the other end of the cable to serial port A on the ‘observed’ machine.
Check the back of your machine for the serial ports labelled “A” and “B”, connect the cable to the appropriate port on each computer. Some Sun machines have only one port marked “A/B”. In this case, the single port acts as both “A” and “B”. If you need the functionality of serial port “A”, you just connect a regular null modem cable to it. However, if you need it to act as serial port “B”, you will need a special Y-shaped adapter cable that ‘splits’ the port into “A” and “B”. If you’re daring enough to try to make your own cable, here is the pinout for you.
3) Establish a tip hardwire session.
On the ‘observing’ machine, type:
tip hardware
You will hear a beep and then see the following response:
connected
Unless the machine is going through POST and diagnostic messages are scrolling up the screen, you will not see anything else. Hit ENTER a few times and depending on what state the machine is in, you will normally see one of three things:
- a “login:” prompt meaning the machine has booted the OS and is waiting for you to log in
- a command-line prompt (usually a “#”) indicating the machine is in the operating system and someone has already logged into it
- an “ok” prompt, signifying that the ‘observed’ machine is at the OBP level
It’s possible for something else to be on the screen, but these are the most common scenarios. If you don’t recognize the screen you see, might I suggest that you probably shouldn’t be futzing around with the machine in the first place 😉
4) How to send a break, terminate the connection, etc…
HOW TO SEND BREAK:
If you need to send a break to the ‘observed’ machine, you cannot simply hit STOP+A. This is because the STOP+A will only have an effect on the machine you are sitting at, causing it to drop the OBP level. In order to send a “STOP+A”, or a ‘send break’ signal to the ‘observed’ machine, you will need to use the following keystrokes:
~#
For those in doubt, that would be the tilde key and the pound or number sign. Yes, it’s a weird key combination. So is CTRL+ALT+DEL 🙂 Anyway, back to business — press tilde, then press pound relatively quickly. Do not press them at the same time.
Sometimes it may not work the first time you do it, for one reason or another. Try it a few times. Keep in mind that you shouldn’t be hitting the keys simultaneously, but you shouldn’t be giving it a full second between keystrokes either.
HOW TO TERMINATE THE CONNECTION:
Ok, so you’re connected to the machine, have done the work you needed to do on it and now you want to go back and work on your own machine. What do you do? To terminate the connection and return to a command prompt on your ‘observing’ machine, use this keystoke:
~.
Again, that would be tilde and period. Just like when you use the ~# keystroke, it may not work the first time around. Try it a few times if it doesn’t take effect right away. When it does receive the signal, it will respond with:
~
[EOT]
and then kick you back to a command line prompt.
NOTE: You should only terminate a tip session in the manner described here. If you terminate it by killing the process, restarting the ‘observing’ machine or any other method, a file will be created which will prevent further tip hardwire sessions. If that’s what you did, sorry — I’ll let you Google your way out of that one.
PS: Don’t forget to stop by AnySystem.com for all your Sun hardware and consulting needs.