| Fri, 21 Feb 1997 20:54:40 +0800 (SGT) |
| < news news@csi.po.my> |
I appreciate if the enlightened ones out there to let me know the products name of the terminal servers which meet the following criteria :- (1) Provides a few RS232 serial ports to WinNT and Win95 operating systems. I am talking about the order of 4-8 ports. (2) Either as a card or a network terminal server. Ethernet attachment preferred. (3) Supports Hardware, Software and none flow control Speed up to 19200 baud max. Higher is better. (4) Can be used inside Visual Basic. That is, Visual Basic serial communication control can use it as though the ports are like the COM1: and COM2: Regards.
| Wed, 26 Feb 1997 18:32:53 -0800 |
| < Alexander Okhotnikov hunter@misery.ecos.kharkov.ua> |
news wrote: Digi International Inc. produce such multiport cards (Digi PC/X,Digi PC/Xe, Digi PC/Xem)with Windows NT and Windows 95 support. You may contact to:
mailto:info@dgii.com
http://www.dgii.com
Digi International Inc.
11001 Bren Road East, Minnetonka, MN, 55343 USA
PH+1-612-912-3444 FX+1-612-912-4952
Digi International Autralia Pty. Ltd.
121 Walker Street, Suite 201, Level 2
North Sydney, NSW 2060 Australia
PH+61 299 29 0299 FX+61 2 99 29 0445
Regards
Alexander Okhotnikov
INEC Joint Firm
mailto:hunter@misery.ecos.kharkov.ua
| Tue, 25 Feb 1997 11:56:05 -0700 |
| < Ivar Rand irand@edpower.com> |
Look at a company called called GMM. They have a card which uses a 486 processor and can handle 8 ports. You will be required to write the software for your protocol. Also there is a company (called Digiboard) selling a product called Digiboard which has com ports these companies have web sites but I don't have their URL handy. We are using the GMM cards and have developed drivers etc. if you wish more info please contact me at ivrand@edpower.com Ivar Rand
| Wed, 26 Feb 1997 16:38:04 +0200 |
| < "Michael J Whitwam" whitwam@global.co.za> |
Digiboard is the most well known multi-port serial card. It comes complete with drivers, and can be used exaclty the same as if it were com1 or 2. Hardware allows you up to 64 serial ports, however Win3.11 and W95 limit you to 9 ports. Under NT, you can have up to 128. My business is writing comms drivers, and I have not yet had a problem with Digiboard.
Mike Whitwam
Wise Technologies (Pty) Ltd
WEB Site - http://www.wisetech.co.za
| Fri, 28 Feb 1997 12:40:41 +0200 (EET) |
| < Iiro Rinta-Jouppi iiro@netcontrol.fi> |
There is one problem you should be aware of if you use radio connections. Digiboard does not know how RTS/CTS flow control is supposed to work. It uses RTS/CTS similar to XON/XOFF flow control. This is very annoying with radio connections. Or more properly, it does not work at all with radio connections. Controlling the carrier requires RTS/CTS flow control. If it works wrong, some bits in the beginning of the message are lost. We have made a auto-handshake modem just to work around this problem since Digi is not willing to correct their product. Otherwise we are pleased to use Digiboard. It works well and does not load the CPU too much.
Iiro Rinta-Jouppi
Design Engineer
Iiro Rinta-Jouppi Email: iiro@netcontrol.fi
Netcontrol Oy Tel: +358 9 4520 200
Tekniikantie 17 Direct: +358 9 4520 2018
02150 Espoo Fax: +358 9 4520 2020
FINLAND WWW: http://www.netcontrol.fi/
| Wed, 26 Feb 1997 10:08:22 -0600 |
| < "David Joy" venus!joyd@sugar.neosoft.com> |
I also have used Digiboards, especially the pc/Xi. This has now been replaced with pc/Xe. Digi sells a toolkit which allows you to write your own FEP/OS (front-end-processor operating system) to download to the pc/Xi and pc/Xe. I have done this and now my I/O drivers can command the Digiboard to do RS-232 handshake control, radio control, timeout detection, etc. This takes the load off of the application. The pc/Xe series uses Intel 80186 (for control) and Zilog 8530 (SCC). Driver support is under Unix (SCO, etc.), Linux, and Microsoft. See Digi at www.digiboard.com.
David Joy
Director Application Engineering
AccessWare, Inc.
----------
| Thu, 27 Feb 1997 09:07:47 -0500 |
| < Khaled Al-akhras (Khaled Al-akhras) KALAKHR@gses.com> |
The Emulex Peformance 4000 will give you up to 32 ports, it connects to the network and uses TCPIP.
| Sat, 1 Mar 1997 10:17:03 +0800 (SGT) |
| < news news@csi.po.my> |
My question to this response is :-
(1) The behaviour is seen on Unix or WinNT/Win95 or both ?
(2) Is there a multiport serial card that work the way you wanted it to be ? Since I haven't bought anything yet, I wouldn't want to use the Digiboard which forces me to use YOUR MODEM :-)
(3) What wrong with using RTS/CTS like Xon/Xoff ? The modem should detect RTS/CTS for flow control and carrier control should go to DCD and DSR. Appreciate your comment.
| Mon, 3 Mar 1997 14:23:00 +0200 (EET) |
| < Iiro Rinta-Jouppi iiro@netcontrol.fi> |
About digiboard RTS/CTS Digiboard hardware does not support RTS/CTS flow control. So it does not depend on operating system. I haven't found one yet. Digiboard works well when you know the limitations. We use Windows NT in our control centre and digiboard is working well in this surrounding. We are a system integrator company. We developed this modem just because we did not find similar from the market. We needed a simple 2 and 4-wire 300/600bps modem that works well with radio lines and does not have any bells and whistles. These days it is very easy to get V34 with all you can ever imagine type modems, but simple telecontrol-modem is harder to find. We are using separate radio and modem since normally radiomodem's radio part is not as good as we want it to be. If somebody knows a good radiomodem that has a good radio part also, please let me know. The ones we have tested caused us a lot of not acknowledged messages and other problems. This was already well answered by Mike Whitwam and Trond Thorman Mike Whitwam wrote: We did this also (with NT), but it ruined our system performance. You have to calculate delays for each baud rate and poll for last bit to go and wait for buffers to be emptied and so on... With digiboard drivers you let the digiboard do all the dirty job and CPU load is minimal. If digiboard would support RTS/CTS flow control all this confusion would be irrelevant. However since it is a hardware feature, they will not repair it. What kind of configuration do other people use in their radio links? What works and what has already proved to fail? Kind regards
Iiro Rinta-Jouppi Email: iiro@netcontrol.fi Netcontrol Oy Tel: +358 9 4520 200 Tekniikantie 17 Direct: +358 9 4520 2018 02150 Espoo Fax: +358 9 4520 2020 FINLAND WWW: http://www.netcontrol.fi/
| Sat, 1 Mar 1997 07:55:06 +0200 |
| < "Michael J Whitwam" whitwam@global.co.za> |
Hi In my case, the solution has been to tell the Digiboard not to use flow control at all, and implement it at the driver level. In my case, I have always used digiboard with custom protocol drivers, so this has not been a problem. As to why RTS/CTS flow control presents a problem, timing! In a radio system you have much longer PTT setup times. When you set the RTS to initiate a transmission, there is a significant delay before the carrier is stable. If you start sending data too soon, well ... Similarly, if you drop RTS to soon after the last character, you destroy it. Nuff said, cheers
Mike Whitwam Wise Technologies (Pty) Ltd WEB Site - http://www.wisetech.co.za
| Sun, 02 Mar 1997 08:55:34 +0000 |
| < "Agust H. Bjarnason" agbjarn@itn.is> |
At 13:56 01.03.1997 -0000, you wrote: XON/XOFF ---SNIP--- ---SNIP--- I have an immediate need for radio modems, and have been looking at modems from Satel in Finland. I would appreciate to learn where I can get modems that do not require handshakng. Regards
Agust H. Bjarnason agust@rt.is RT Ltd, Iceland
============================================================
TF 3 OM Agust H. Bjarnason
Rafm.verkfringur
| El.Eng.MSc. RT-Ltd
___/v\___ PO Box 8555 IS-128
-===(~)=(.*.)=(~)===- Reykjavik Iceland
`- FAX +354- 5687556
Control Engineering E-mail agust@rt.is
================= http://www.rt.is ======================
| Mon, 3 Mar 1997 08:19:58 -0700 |
| < Ivar Rand irand@edpower.com> |
There is a company in Montreal Canada that has a Modem and Radio combined you may wish to consider. The company is called DATARADIO they are also on internet. Ivar Rand
| Mon, 3 Mar 1997 16:28:35 +0000 |
| < "Alain Champagne" dri!ac!alain@vhf.dataradio.com> |
Thanks Ivar, In regards to radio modems to be used without handshake, we have a async. packet radio modem (Dataradio APR) wish is being used when no other radio modems can work properly. Please take a look at the specs. on our Web site. If you need more info. please contact us by phone or E-Mail. Best Regards, Salutations
Alain Champagne achampagne@dataradio.com Dataradio Inc. Phone (514)737-0020 Fax (514) 737-7883
| Mon, 3 Mar 1997 23:20:10 -0600 |
| < "David Joy" venus!joyd@sugar.neosoft.com> |
I would like to help clear up some misconceptions I have seen here lately concerning modems with radio control. First, the Digiboard (for sure the pc/Xi and pc/Xe series) hardware *does* support RTS/CTS. It is controllable from the firmware FEP/OS loaded down to the board during OS boot. Digi sells a toolkit to allow you to write your *own FEP/OS*. We have done this. We download our FEP/OS during OS boot and our firmware controls RTS/CTS and other important radio comm parameters (such as CHANNEL BUSY). Second, the OS *does* determine whether you will have RTS/CTS control. For example, the standard UNIX driver (also supported by Digi) dictates that RTS go HIGH when the port is opened, and go LOW when the port is closed. This is great for leased line or dial-up modems, but does not do you any good for radio (it simply keys the transmitter until you close the port). Just wanted to set the record straight. You can contact me individually for more info, or I will put in my two-cents worth when I feel it necessary.
David Joy Dir Appl Engr AccessWare----------
| Tue, 4 Mar 1997 20:09:19 +0200 |
| < "Michael J Whitwam" whitwam@global.co.za> |
More Digiboard RTS stuff Digiboard supports the standard windows comm drivers in all flavours of windows. There are standard windows API calls for setting and clearing the RTS line. These functions can however only be used for slow turn around devices, where timing is not critical. We run our comms on a state machine, serviced typically every 200 ms. Logic goes something like
T1 Set RTS
T2 Send message
T3 ... Message sent loop?
Tn Clear RTS