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#144764 - 20/02/2003 18:06 Serial Port / Modem Sharing over a LAN
Shonky
pooh-bah

Registered: 12/01/2002
Posts: 2009
Loc: Brisbane, Australia
I ask here after some googling since I know I will get the best answer

Most of our products are connected via modems (GSM and PSTN). Quite a few of the engineers and apps engineers need the ability to dial out to these devices. Currently we have a patch panel and have to keep changing when a different user wants a phone line since we only have a few spare.

What I would like is some server software that runs and has access to a number of comports physically on the server. These all connect to modems that have permanent phone lines. On the client side, we install a special driver that results in a virtual COM port appearing on the client. Then whenever the client opens the COM port it connects to the server and server assigns it the first available real comport.

If you have ever seen SAPS, that's what I would like. But I'm looking for something free. Can run on an NT server or Linux, I don't mind, but the clients basically need to be 98 / 2000 / XP.

Does anyone know of one that's free or particularly cheap?

Thanks
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Christian
#40104192 120Gb (no longer in my E36 M3, won't fit the E46 M3)

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#144765 - 20/02/2003 18:17 Re: Serial Port / Modem Sharing over a LAN [Re: Shonky]
matthew_k
pooh-bah

Registered: 12/02/2002
Posts: 2298
Loc: Berkeley, California
Hmmm, what you want is an old school terminal server, and some software that may or may not exist. Back in the day, I set up a livingston port master which had the ability to telnet to any of its serial ports. All you'd need then is a virtual serial driver for windows.

Matthew

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#144766 - 20/02/2003 18:37 Re: Serial Port / Modem Sharing over a LAN [Re: matthew_k]
lectric
pooh-bah

Registered: 20/01/2002
Posts: 2085
Loc: New Orleans, LA
Since it's for your company, I'd recommend something like the Equinox Box. Kinda pricey, but they work REALLY well.

We use several at work.

Although something like THIS seems like more your need.


Edited by lectric (20/02/2003 18:40)

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#144767 - 20/02/2003 18:38 Re: Serial Port / Modem Sharing over a LAN [Re: matthew_k]
ricin
veteran

Registered: 19/06/2000
Posts: 1495
Loc: US: CA
Yes, a Livingston (now Lucent) Portmaster. Usually used for dial-in, but you should be able to do what you have described as well. The only thing I don't think exists, yet, is the virtual serial port Windows driver as you described it.
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Donato
MkII/080000565
MkIIa/010101253
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#144768 - 20/02/2003 18:41 Re: Serial Port / Modem Sharing over a LAN [Re: lectric]
ricin
veteran

Registered: 19/06/2000
Posts: 1495
Loc: US: CA
Ok, scratch the Portmaster idea. Looks like the Equinox is exactly what you need.
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Donato
MkII/080000565
MkIIa/010101253
ricin.us

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#144769 - 20/02/2003 18:43 Re: Serial Port / Modem Sharing over a LAN [Re: ricin]
lectric
pooh-bah

Registered: 20/01/2002
Posts: 2085
Loc: New Orleans, LA
Yip, there is, see second link above.

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#144770 - 20/02/2003 19:10 Re: Serial Port / Modem Sharing over a LAN [Re: lectric]
Shonky
pooh-bah

Registered: 12/01/2002
Posts: 2009
Loc: Brisbane, Australia
Thanks for the suggestions. Spartacom used to make SAPS so yeah that is really what I'm looking for. You're right, the Equinox box is probably not quite I'm looking for.

The Spartacom stuff has pools meaning you can have one COM port on the client and that automatically selects the next free server port - the user doesn't care which comport he gets. The Equinox seems to map a COM port on the server end to a com port on the client. So for each comport on the server, you'd need a comport on the client. Correct?

However the operative word is free or cheap. The Spartacom stuff is US$1k which might not seem expensive to you, it is expensive for us, since my boss won't spring for something he can't see a financial advantage in - Not easy to bullsh** him either.
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Christian
#40104192 120Gb (no longer in my E36 M3, won't fit the E46 M3)

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#144771 - 20/02/2003 21:39 Re: Serial Port / Modem Sharing over a LAN [Re: Shonky]
lectric
pooh-bah

Registered: 20/01/2002
Posts: 2085
Loc: New Orleans, LA
Well, the equinox box is really that you telnet to the box and get a specific port. Rather like a print server.

The Sparta Software is more like what you're describing. You have a server with like 6 ports in it. The clients have on e "virtual" com port that is in reality an ethernet device. Whenever the server gets a request, it pools to the next available com port and modem that's free. No real serials are used on the clients at all. I'm beginning to wonder if there isn't a shareware/freeware version of something similar. It seems it wouldn't be that hard to write. 'Course, I'm a non-coder, so it all seems like it would be easy to me, all safe in the fact that I'll never attempt it.

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#144772 - 20/02/2003 21:56 Re: Serial Port / Modem Sharing over a LAN [Re: Shonky]
lectric
pooh-bah

Registered: 20/01/2002
Posts: 2085
Loc: New Orleans, LA
Interesting... looks like it's built into MS Small business Server.

Here

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#144773 - 20/02/2003 22:38 Re: Serial Port / Modem Sharing over a LAN [Re: lectric]
robricc
carpal tunnel

Registered: 30/10/2000
Posts: 4931
Loc: New Jersey, USA
_________________________
-Rob Riccardelli
80GB 16MB MK2 090000736

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#144774 - 20/02/2003 22:53 Re: Serial Port / Modem Sharing over a LAN [Re: robricc]
Shonky
pooh-bah

Registered: 12/01/2002
Posts: 2009
Loc: Brisbane, Australia
Well I definitely want to do everything on the "level". I am seriously considering writing my own as lectric has suggested since I probably can't get anything for the right price.

Sooo.... now I'm looking for some howtos on writing device drivers. Network code is easy for me so the server end should be pretty easy. Just the client code stuff basically. Off to google I go - unless someone can point me straight at something concise
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Christian
#40104192 120Gb (no longer in my E36 M3, won't fit the E46 M3)

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#144775 - 21/02/2003 14:27 Re: Serial Port / Modem Sharing over a LAN [Re: Shonky]
number6
old hand

Registered: 30/04/2001
Posts: 745
Loc: In The Village or sometimes: A...
Hi Shonky, and how much money do you reckon your boss will end paying you in wages/salary to write this bit of software?
And what will the opportunity cost of lost time and other productivity sapping hassles your expensive engineers and tech support people will end up frittering away while they juggle cables to save a measley $1K?

If you're writing the software "out of band" i.e. out of hours, then your boss is a smart man - getting his workers to do it for him for free.

If you're being paid to write it during working hours, spend 30 minutes and put up a business case to your boss of how much it would *really* cost [and don't underestimate] them to pay you to do it, and factor in the others (and your) time involved to keep the current system going.

If your boss is a good manager he will see the light and let you buy the other software.

But make sure the other software will work as its supposed to - but given its pedigree I doubt it won't work.


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#144776 - 23/02/2003 05:55 Re: Serial Port / Modem Sharing over a LAN [Re: number6]
Shonky
pooh-bah

Registered: 12/01/2002
Posts: 2009
Loc: Brisbane, Australia
I knew someone was going to say that. I'm kinda of interested just for the sake of a learning exercise. i.e. I was going to do it "out of band"

I do have an older version of the SAPS stuff that won't work on XP clients and does seem to work as advertised, so I assume this newer MPNT will too. Perhaps I can get an upgrade.... I can it seems and will probably go for that now.

Thanks guys. If anyone knows of any device driver type stuff, let me know because I'm still interested.
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Christian
#40104192 120Gb (no longer in my E36 M3, won't fit the E46 M3)

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#144777 - 03/03/2003 16:54 Re: Serial Port / Modem Sharing over a LAN [Re: Shonky]
tman
carpal tunnel

Registered: 24/12/2001
Posts: 5528
Bit late but it may help

I'm looking at some of the Lantronix's embedded chips and came across a free network serial port sharing utility on their page. It's here. I've not tried it personally but you may want to try it out yourself as it's free anyway.

- Trevor

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#144778 - 04/03/2003 20:59 Re: Serial Port / Modem Sharing over a LAN [Re: tman]
Shonky
pooh-bah

Registered: 12/01/2002
Posts: 2009
Loc: Brisbane, Australia
Thanks tman. It sort of gives one half of the solution. i.e. it makes a virtual COM port into a TCPIP connection. I would still need something at the other end to convert the network connection back to a serial (which is what their hardware products actually do).

I'm going with the MPNT. I just need to find someone interested in actually selling me a copy. That techarts mob seem quite disinterested so far.
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Christian
#40104192 120Gb (no longer in my E36 M3, won't fit the E46 M3)

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#144779 - 05/03/2003 04:10 Re: Serial Port / Modem Sharing over a LAN [Re: Shonky]
tman
carpal tunnel

Registered: 24/12/2001
Posts: 5528
Yeah. But I was thinking that their software would be replacing the harder half of the project as you wouldn't need to mess about trying to write a VxD under Windows.

It's crazy how sometimes you know exactly what you want but nobody seems to want to sell it to you. I've spent ages once trying to buy a particular adapter but nobody stocked it and the distributors wanted me to buy 30x of them.

- Trevor

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#144780 - 05/03/2003 04:19 Re: Serial Port / Modem Sharing over a LAN [Re: tman]
Shonky
pooh-bah

Registered: 12/01/2002
Posts: 2009
Loc: Brisbane, Australia
True, true. I may still go this route since

a) I'm finding it difficult to purchase and
b) I'm having major issues getting the demo to work on our server. It has all these security and accounting features which necessitate a database (SQL, Access etc). I already have the SQL server but can't get their software to talk to it properly. And I don't know whether I even want all this extra "stuff"
_________________________
Christian
#40104192 120Gb (no longer in my E36 M3, won't fit the E46 M3)

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