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Join Date: Feb 2008
Posts: 4

Modem to modem woes...

02/21/2008 3:49 PM

I am trying to remote connect from a pc at my office to a pc at our central tower which houses our paging system database. I was using hyperterminal at the tower to test the connection and am able to dial into the same computer that we are using at our office but am unable to connect from the opposite direction. Any suggestions on where to go from here would be greatly appreciated.

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Guru
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#1

Re: Modem to modem woes...

02/21/2008 4:11 PM

Hello caba004

Surely you would have Routers at each site.

If so, check your Router settings. You perhaps have to open a normally closed Port or two.

For help re the Router, refer: http://portforward.com/ and look for your particular router there.

Likewise you use a Software Firewall at each Computer? Of course you do, because otherwise you'll have malware racing in to hijack your Computer.

Check your Software Firewall at each end, http://portforward.com/ may also assist you there.

Most Software has a "Help" facility.

Security Software in a Computer may often prevent proper access, because its settings are to "prevent unauthorised access", and if that is the case, you need to alter setting/s on that/those Security Utility/Utilities.

Advise further here, thank you.

Kind Regards....

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#2
In reply to #1

Re: Modem to modem woes...

02/21/2008 4:28 PM

unfortunately it's not that simple, the computer i am connecting to is running os/2 (I KNOW! GET WITH THE TIMES RIGHT?) the only way i can connect is through the serial ports which is what the modem is connected to. I cannot run ethernet from our router (the only reason we have a router to begin with is for an e-mail paging server) to the os/2 computer (which doesn't even have highspeed internet/network capabilities).

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Guru
New Zealand - Member - Interested in everything- see my Profile please APIX Pilot Plant Design Project - Member - Member Engineering Fields - Electrical Engineering - Member Engineering Fields - Power Engineering - Member Engineering Fields - Civil Engineering - Member Hobbies - Musician - Autoharp and Harmonica Hobbies - Hunting - Member Hobbies - Fishing - Member

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#3
In reply to #2

Re: Modem to modem woes...

02/21/2008 4:54 PM

Hello again caba004

I well remember OS/2, which was vastly superior to the then Windows Operating System.

Far more secure too, which is a problem you are now facing.

Long ago, IBM decided to let OS/2 fall by the wayside.

The singular advantage of OS/2 is that it is less likely to be targeted by malware, but that is its only advantage now.

Most OS/2 users have "bitten the bullet", discarded OS/2, and migrated to more recent Operating Systems, along with compatible software.

A few questions for you, to help with diagnosis:

  1. What physical distance is between the two computers?
  2. Are the two computers on the same property, or are they separated by roads or other properties?
  3. What O/S are you running in your other computer?
  4. Do you run special software that can only be run on OS/2 in that Computer?

I see that OS/2 can have USB drivers: Refer Google OS/2 USB support

The USB connection may be the easiest way to connect, providing the other computer has USB fitted.

Advise further, thank you.

Kind Regards....

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#4
In reply to #3

Re: Modem to modem woes...

02/21/2008 5:23 PM

In answer to your questions...

1. Appx 36 miles from office to tower.

2. Each computer is at a different physical location.

3. Windows XP on the office computer, OS/2 Version 3 on tower computer (we are connecting through ProComm Plus.

4. The software running on the tower computer is actually called InfoLink. It was designed for use in paging systems. It converts the info coming in off our DID trunks into info that it broadcast out on an analog 72.4800 MHz transmitter which then goes out to our other sites and gets rebroadcast as digital 152.2400 MHz.

Although as of this moment I am working off a Windows 2000 Laptop in HyperTerminal. Like I said I am able to connect from the tower to the office, but not from the office to the tower, even to the laptop. I already had AT&T out here to check that there wasn't a problem with the line. Hooray for having to pay them even more money!

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Guru

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#5
In reply to #4

Re: Modem to modem woes...

02/22/2008 12:29 AM

OK. Are both computers equipped with a working (and compatible) PPP stack?

Is there some sort of terminal server or other device you're connecting through at the office when you connect to the office from the tower? If yes, do you have the same type of terminal server (switch) at the tower?

At the tower, does incoming traffic have to go through a switch or router that provides port-duplication or firewalling or anything that might discriminate against particular traffic coming in on ports?

Are you running VLANs at the tower?

Let me know.

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#6
In reply to #5

Re: Modem to modem woes...

02/23/2008 11:59 AM

I'll definately have to check on the PPP stack, didn't think to check that.

There are no devices connected, however I did read in all my research on this that some usb to serial converters will not recognize flow control. I have to pick up an internal modem for the PC and attempt to connect in this manner.

To clarify, currently, the setup is: office pc->serial modem->office phone line-tower phone line->tower serial modem->tower pc

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Guru

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#7
In reply to #6

Re: Modem to modem woes...

02/24/2008 1:56 AM

So these are not internal modems. They're both external modems to their respective PCs? If yes, are the modems the same make and model?

Can you test to see whether the two modems can sync-up and exchange signals with each other?

Also, a wild guess, but I would check the OS/2 machine to see that it had all the NetBUEI and NetBIOS stuff necessary and that their corresponding config files were set appropriately. OS/2 is an old and interesting operating system, but as I remember, it was far from Plug-n-play!!!

Hope that helps.

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#8
In reply to #7

Re: Modem to modem woes...

02/24/2008 12:47 PM

yes the external modems are both zoom modems, one is a v.92 but is capable of v.34, the other is a v.34.

The two modems can sync up and talk, but only if the connection is from the tower side, not from the office side. The modems will only sync if the I dial from the tower to the office, it will not sync if the office dials the tower.

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Guru

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#9
In reply to #8

Re: Modem to modem woes...

02/25/2008 12:39 AM

So is it possible that when dialing one way, the modem auto-senses v.34 and configures itself automatically, but going the other way, that modem defaults to v.92, which the other modem can't do?

Just a thought.

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