Need help with HP 48sx file transfer


I am trying to install some libraries on my 48sx, and having some issues. The first time I try to upload a file to the 48, it works OK, but try another file, and I get a dialog box that says "There was insufficient memory to complete this operation." Not sure if this message is coming from HP48 Explorer or Windows.

If I close HP48 Explorer and reopen it, it works again the first time, then repeats the problem.

Restarting HP48 Explorer each time is a workaround, but this should not be necessary, Any suggestions? Thanks.


What exactly is "HP48 Explorer" ?


HP48 Explorer is the Windows file transfer utility by Chris Mumford available from An alternative to the HP software.


OK, I was not aware of this. I have always used a DOS computer and Kermit. Does it work with the serial RS232 port?


I am using a Belkin USB-RS232 converter, which is seen by HP48 Explorer as COM5. That part seems to work OK.


Hi, Martin;

what version of Windows are you using? I am not quite sure if the HP48 Explorer works fine under XP, but I remember testing it OK with W95 and W98. Do you have an old PC running one of these to try it out?

Sorry not being of much help... :^(

Luiz (Brazil)

Edited: 7 Nov 2009, 10:01 p.m.


The 48sx doesn't have sufficient memory to do the transfer. Doing the transfer in binary mode instead of ACSII mode save some memory. But since the SX only has 32K RAM it could run out of memory.


Hi, Chan Tran;

since he says the operation succeeds after closing and opening the HP48 Explorer, do you believe the message is genuinely related to the HP48SX being out of memory? It seems to me it is something else, related mostly to the computer's O.S.

Any ideas?


Luiz (Brazil)


do you believe the message is genuinely related to the HP48SX being out of memory?

You are right, I failed to mention I have 160k system RAM.

I am running XP, and HP48 Explorer otherwise seems to work.


I don't recommend Vista.



I've never had any problems using Kermit with any 48/50 connected to any PC (Windows, Mac, Linux, UNIX). Have you considered using that?

Kermit HOWTO:

  1. Get Kermit for your platform (Google it).
  2. Put all your HP files in a single directory, start up Kermit from that directory.
  3. Type the following commands (BTW, you can put this in the Kermit initialization file (read the docs)):
    C-Kermit>set line COM5: (or whatever)
    C-Kermit>set speed 9600
    C-Kermit>set carrier off
    C-Kermit>set parity none
  4. Setup the SX for binary or ASCII.
  5. From the SX, enter the filename you want in single quotes, e.g. 'FOO', then KGET.
  6. Repeat last two steps until you have all the files.
  7. Ctrl-C Kermit server mode. 'exit' to exit.


Thanks, Egan, and everyone for your suggestions. I read the section in the Owner's Manual on Kermit, and it states "To transfer data to and from a computer, the computer must be running a program that implements Kermit protocol." My guess is, that's what HP48 Explorer does.

So the manual seems to say that Kermit is a protocol, but Egan, you seem to be suggesting that there are programs called Kermit.


Hi, Martin;

Kermit is a protocol and also a set of programs. Please, have a brief intro here. It is also free.

From wikipedia:

Naming and copyright

Kermit was named after Kermit the Frog from The Muppets. The program's icon in the Apple Macintosh version was a depiction of Kermit the Frog. A backronym was nevertheless created, perhaps to avoid trademark issues, KL10 Error-Free Reciprocal Microprocessor Interchange over TTY lines.

Kermit is an open protocol - anybody can base their own program on it, but some Kermit software and source code is copyright by Columbia University.

Sorry, I could not resist


Luiz (Brazil)

Edited: 10 Nov 2009, 3:01 p.m.


Thanks, Luiz.

Well, I see Kermit sells for $50-$75, so I think I will stick to HP48 Explorer, and use my $50 for other purposes.


The free DOS version works fine in Windows, but you may be limited to COM1:-COM4:. I have not used it in a while.

For all non-Windows users C-kermit is free. I could not find C-kermit for Windows.


I agree with Egan that the DOS Version works fine on XP.

I personally find that the Kermit protocol is too slow for many cases. In the early beginng of my SysRPL career it took me about 30 min. to restore the 100kB of my 48SX home directory. In the last 10 years I use a XModem Library on the SX. Now the restoring process takes about 2-3 min. over XModem.

Another way is to use Emu48 on the PC as Kermit program. I just load the file I want to send with "Load Object..." into Emu48, bound the COM port with the real 48SX in the Emu48 settings dialog to Wire. And then you have the choice, start the Kermit-server on real calculator or on the emulated one. I prefer the server on the real calc and using the SEND command on the emulated one.


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