SUCCESSFULLY CONNECTED old HP LaserJet 6MP to my new iMac
As Apple still supports that printer, you should have no problems, but it will depend on your setup:
https://support.apple.com/en-ca/HT201465
I actually have an older HP Laserjet 4ML networked and setup that can also do wireless printing with all our Macs and iPads, and it needs AppleTalk and uses a Mac serial DIN connector. But we also use an old Mac in the background running OS X 10.5.8 as it was the last to support AppleTalk, and it's usually just sleeping.
At least you won't need to use an AsanteTalk Ethernet/AppleTalk adapter as we do, but I don't know if any networked Apple Airport base would support that printer to help with wireless printing.
I had my perfectly healthy old workhorse of a printer - HP LaserJet 6MP (from 1997) - connected to my old iMac (2006... running Snow Leopard) via that AsantéTalk Ehternet to LocalTalk converter. (I got the printer long before the old iMac, but was very happy to find that it worked once I bought and connected the AsantéTalk gadget). Now I've just started using a new-ish iMac (late 2013 model) and all sources indicated that I would no longer be able to use my LaserJet 6MP.

I tried for a few stubborn days to get it to work, simply certain that all the info I'd found from Apple, HP, and other sources including this forum were simply incorrect. Then I gave up and went to Staples and bought a brand new HP LaserJet. Got a really good Thanksgiving weekend deal, set it up and it's great. Now, I'm still transferring everything from my old iMac to my newer iMac (running Yosemite) and this morning, in my stubbornness, I decided to have one last go at connecting. And, much to my overwhelming surprise, I DID get it to work!! I may still now sell or donate that old 6MP, but it does indeed work with the new iMac! This info might relieve the anxiety I've had about this and save someone from having to put out the cost of a new printer and get rid of their 6MP.
What you need:
- First, you need to have the AsantéTalk gadget! I bought it years ago on EBay for $20. Asanté doesn't make it or sell it anymore, but I find it's on Amazon. http://www.amazon.com/dp/B00004VUFW/?tag=macforums0e4-20
My AsantéTalk converter has still been connected to my AT&T router (I have no memory of how I did that years ago, though I do remember it was also a series of trial and error and experimenting. I have been consulting the Asanté manual to try and solve the iMac to printer dilemma, but it doesn't help much). I made no alterations to that connection. The AsantéTalk has been allowing wireless printing from the old iMac across the room to the 6MP for 9 years, without issue.
- The HP driver - I downloaded the driver from the HP website and installed it on the new iMac. I found it via an internet search. I'd done this during one of my earlier attempts to connect. The driver is HP LaserJet 6P/6MP 19.13. (my old Mac used version 19.8)
- Ethernet cable
- Wireless-enabled router. (Mine's the one I got from AT&T, my internet provider.)
- The IP address of that internet connection. (you have to find out what that address is for your network. It's a series of numbers, separated by periods. Such as this randomly made-up IP address: 123.345.4.78)
Steps I took:
- Installed HP driver on iMac. (you might already have it.)
- Connected the iMac to the router via Ethernet cable. (This was key! And the last thing I thought of. I got to the wireless aspect after successful installation.)
- Opened iMac's System Prefs and (in the Network settings) verified that the Ethernet was connected.
- In Printers & Scanners setting, I deleted the 6MP that I'd added there earlier as a result of my unsuccessful previous attempts.
- Clicked the + sign to add a "new" printer.
- In the "Add" window, I clicked "IP" (instead of "Default").
- In the Address field, I entered the IP address of my AT&T network
- Once I did that, below the Address appeared confirmation that my IP address was valid. "Valid and complete host name or address". (I got stuck here earlier, but that was before I connected the Ethernet cable.)
- In the "Protocol" field, I left the default I had there, which was "HP Jetdirect - Socket".
- I left the "Queue" field blank
- In the "Name" field you could personalize that printer's name for identification purposes if you have more than one printer or wireless device. I put "HP LaserJet 6MP". If you give it no customized name, the IP address will be listed as the name.
- I left the "Location" field blank. (I imagine that you could put whatever you want there, such as "Joe's office" or "Front desk".)
- In the "Use" field, I chose "Other". (Autoselect did not do the trick.) A Finder window opened, and I needed to find that 6MP driver. It is not easy to locate. I found it in my Macintosh HD's Library > Printers > PPDs > Contents > Resources. (It's among the list of the zillion other HP drivers that were installed when I did that driver installation.) Chose "HP LaserJet 6MP.gz" and clicked "Open".
- Clicked "Add" and the 6MP appeared in the list of Printers in the "Printers & Scanners" window.
- Did a test print of a simple TextEdit document. It worked. Printer was connected to new iMac. Hooray!
What about the WIRELESS connection, you ask.
- I just
disconnected the Ethernet cable and voila!… the printer's connection still worked.
So, yes, I can now use my old printer. Whew! Now I have two HP printers. I don't need two. I think the old one will be finding a new home, but I sure do love solving a puzzle. Good luck. I hope this helps somebody.