How connect PC Embedded to MDB (Vending Machine)
in [Embedded]
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From: Paul Keinanen on 29 Sep 2008 16:07 On Mon, 29 Sep 2008 11:32:31 +1000, "PhilW" <phil(a)microcoin.com> wrote: > ><juanma.freelance(a)gmail.com> wrote in message >news:c4d5b1b0-ea81-446b-ba2a-4f7ebe2811c3(a)l64g2000hse.googlegroups.com... >> Hi! >> >> I'm sorry but I am not English and I speack English very bad. >> >> My question is: How connect a PC Embedded to Vending Machine? I know >> that exist a protocol MDB that is used by vending machine, but this >> conector is different to pc conector (RS232, USB, i2c, etc). Can I >> connect a PC Embedded by MDB? How? >> >> Anybody understand me? >> >> Thanks you! > >We understand you. > >Read the spec to understand what is required to connect. > >However, even once you have done the hardware to be able to connect to a >PC's RS232 port you will, more than likely run into the problem of the 9bit >char format not being supported on a std PC serial port. This is the tricky part. Unless you are prepared to do very low level coding, the only thing I have found so far is some ethernet to 9bit serial converters done by Port Box in Prague. >You can fudge it using the mark/space parity control but it is not very >nice. This is OK for slow speeds and as long as you are able to disable the interrupts. Paul
From: cs_posting on 29 Sep 2008 16:39 On Sep 29, 3:46 pm, juanma.freela...(a)gmail.com wrote: > I need to create adapter for MDB to any port (serial?) the PC ... it > is difficult? I know computer science, but the electronic... :( any > idea? How about doing your own MDB-USB adapter using either the FT232 or related (if it can do 9-bit serial) or some more capable USB microcontroller. You could even use a microcontroller as a bridge between 8 and 9 bit serial. What you would want to do is check microcontrollor data sheets and find one with a serial port that can be programmed to 9 bits.
From: PhilW on 29 Sep 2008 21:09 <juanma.freelance(a)gmail.com> wrote in message news:73aaa712-5e75-4674-a2b2-3a62b78569a3(a)p25g2000hsf.googlegroups.com... On 29 sep, 20:29, James Beck <j...(a)reallykillersystems.com> wrote: > In article <29c16500-d3a1-4d46-a7d4- > 59492ef13...(a)w7g2000hsa.googlegroups.com>, juanma.freela...(a)gmail.com > says... > > > > > On 29 sep, 17:56, James Beck <j...(a)reallykillersystems.com> wrote: > > > In article <3834d44e-355e-4d5f-af57-87e9ec4c0a97 > > > @z72g2000hsb.googlegroups.com>, juanma.freela...(a)gmail.com says... > > > > > On 29 sep, 16:33, James Beck <j...(a)reallykillersystems.com> wrote: > > > > > In article <1da3a443-e530-487a-8cb7-e4166e206414 > > > > > @i76g2000hsf.googlegroups.com>, juanma.pal...(a)gmail.com says... > > > > > > > On 29 sep, 11:11, juanma.freela...(a)gmail.com wrote: > > > > > > > On 29 sep, 03:32, "PhilW" <p...(a)microcoin.com> wrote: > > > > > > > > > <juanma.freela...(a)gmail.com> wrote in message > > > > > > > > >news:c4d5b1b0-ea81-446b-ba2a-4f7ebe2811c3(a)l64g2000hse.googlegroups.com... > > > > > > > > > > Hi! > > > > > > > > > > I'm sorry but I am not English and I speack English very > > > > > > > > > bad. > > > > > > > > > > My question is: How connect a PC Embedded to Vending > > > > > > > > > Machine? I know > > > > > > > > > that exist a protocol MDB that is used by vending machine, > > > > > > > > > but this > > > > > > > > > conector is different to pc conector (RS232, USB, i2c, > > > > > > > > > etc). Can I > > > > > > > > > connect a PC Embedded by MDB? How? > > > > > > > > > > Anybody understand me? > > > > > > > > > > Thanks you! > > > > > > > > > We understand you. > > > > > > > > > Read the spec to understand what is required to connect. > > > > > > > > > However, even once you have done the hardware to be able to > > > > > > > > connect to a > > > > > > > > PC's RS232 port you will, more than likely run into the > > > > > > > > problem of the 9bit > > > > > > > > char format not being supported on a std PC serial port. > > > > > > > > > You can fudge it using the mark/space parity control but it > > > > > > > > is not very > > > > > > > > nice. > > > > > > > > > Why don't you use ccTalk instead?www.cctalk.org > > > > > > > > > regards > > > > > > > > PhilW > > > > > > > > Thanks you. > > > > > > > > I dont understand all, what is "ccTalk"?? > > > > > > > > regards. > > > > > > > Juanma.- Ocultar texto de la cita - > > > > > > > > - Mostrar texto de la cita - > > > > > > > I read a little about spec of "ccTalk", and this is other > > > > > > protocol, > > > > > > no? > > > > > > > I need "to talk" with a vending machine. The standard of vending > > > > > > machine is the MDB (i think). > > > > > > > Are you understand me? > > > > > > > Thanks you. > > > > > > regards. > > > > > > Here is a USB to MDB bridge > > > > > :http://www.geocities.com/bonusdata/analyzer/mdb_interface/mdb_interface. > > > > > htm > > > > > (sorry for the spanning) > > > > > > Here is the protocol :http://www.vending.org/technical/MDB_3.0.pdf > > > > > >www.vending.orgiswhereyou need to go for any info about MDC/ICP- > > > > >Ocultar texto de la cita - > > > > > > - Mostrar texto de la cita - > > > > > Thanks you!! > > > > > I know this all, but the "USB to MDB" is not a good solution for me, > > > > should be others solutions... > > > > > I am interesting in ccTal PhilW but i dont understand how apply this > > > > to the vending machine. > > > > If the vending machine does not speak CCTalk then there is no way to > > > apply it at all, in this case. MDB/ICP is the way you will have to go. > > > CCTalk was designed more along the lines of gaming systems and MDB was > > > designed for vending machines and the like. Not that you couldn't use > > > CCTalk in a vending machine, but MDB was standardized for use in them > > > (vending machines) long ago.- Ocultar texto de la cita - > > > > - Mostrar texto de la cita - > > > Oh James Beck, i think that you have reason. > > > My problem is how comunicate the pc embedded with vending machine with > > the protocol MDB... If the unique solution the "MDB --> USB adapter"? > > If you sum the price that a pcembedded+adapter ... for one for machine > > is very expensive no? it must of having another solution, no? > > > Thanks you! > > regards. > > Well, if you doing a one off machine, there will never be any economy of > scale. If I were doing a single machine/test station, I wouldn't balk > at paying the price for the adapter. If I were doing thousands of them > I would look at doing something more task specific and cheaper. You can > implement the protocol yourself with some kind of adapter for the PC and > a communications library, but that would be what the specification is > for.- Ocultar texto de la cita - > > - Mostrar texto de la cita - Oh, I see that you understand me :) I need to create adapter for MDB to any port (serial?) the PC ... it is difficult? I know computer science, but the electronic... :( any idea? Thanks you! regards. An adaptor is not an easy thing to do, simply due to the fact you need to maintain the timing specifications of the MDB protocol. An adaptor that just recieves a command from the PC, re-formats it for MDB and then sends it on, waits for the response and forwards that to the PC will easily break the timing criteria of the protocol, considering that each char takes 1mS to transmit or receive. Concerning USB adaptors. Can be good providing they support, and implement the mark/space parity support correctly. However, you still have to provide low level coding to fudge the 9 bits via the mark/space parity. In addition you will be required to add timing delays to ensure the parity changes are sent over USB before transmitting the next data or parity change. We have had success with the CP2102 from silicon Labs. It is sure however, from experience, that supporting MDB over USB is a lot more painful than a standard serial port. Another alternative is to acquire an add-on serial port that natively supports 9 data bits at the hardware level. Not cheap, hard to find and expensive. As for the vending machine implementation, you have not said, but I conclude that YOUare building the vending machine and YOU therefore have control over the protocol to use. Unless by some specification requirement that you use MDB, I see no reason why you cannot use ccTalk. I believe the "protocol" is purely for internal machine use, aimed at connecting all peripherals to a host controller, namely your embedded PC. Any external communications is usually by some other communications link, modem, ethernet, wifi, etc. Why ccTalk? It's simple and most importantly can be easily supported by any PC serial port, USB adaptor etc that supports the standard 8bit char length. It could be any other protocol besides, that uses the 8bit data length as well. It's just that ccTalk is well documented, well supported and widely used. We produce products that support both MDB and ccTalk in addition to others. We much prefer ccTalk for its non requirement of the 9bit data format. regards PhilW
From: juanma.freelance on 30 Sep 2008 04:11 On 30 sep, 03:09, "PhilW" <p...(a)microcoin.com> wrote: > <juanma.freela...(a)gmail.com> wrote in message > > news:73aaa712-5e75-4674-a2b2-3a62b78569a3(a)p25g2000hsf.googlegroups.com... > On 29 sep, 20:29, James Beck <j...(a)reallykillersystems.com> wrote: > > > > > > > In article <29c16500-d3a1-4d46-a7d4- > > 59492ef13...(a)w7g2000hsa.googlegroups.com>, juanma.freela...(a)gmail.com > > says... > > > > On 29 sep, 17:56, James Beck <j...(a)reallykillersystems.com> wrote: > > > > In article <3834d44e-355e-4d5f-af57-87e9ec4c0a97 > > > > @z72g2000hsb.googlegroups.com>, juanma.freela...(a)gmail.com says... > > > > > > On 29 sep, 16:33, James Beck <j...(a)reallykillersystems.com> wrote: > > > > > > In article <1da3a443-e530-487a-8cb7-e4166e206414 > > > > > > @i76g2000hsf.googlegroups.com>, juanma.pal...(a)gmail.com says... > > > > > > > > On 29 sep, 11:11, juanma.freela...(a)gmail.com wrote: > > > > > > > > On 29 sep, 03:32, "PhilW" <p...(a)microcoin.com> wrote: > > > > > > > > > > <juanma.freela...(a)gmail.com> wrote in message > > > > > > > > > >news:c4d5b1b0-ea81-446b-ba2a-4f7ebe2811c3(a)l64g2000hse.googlegroups.com... > > > > > > > > > > > Hi! > > > > > > > > > > > I'm sorry but I am not English and I speack English very > > > > > > > > > > bad. > > > > > > > > > > > My question is: How connect a PC Embedded to Vending > > > > > > > > > > Machine? I know > > > > > > > > > > that exist a protocol MDB that is used by vending machine, > > > > > > > > > > but this > > > > > > > > > > conector is different to pc conector (RS232, USB, i2c, > > > > > > > > > > etc). Can I > > > > > > > > > > connect a PC Embedded by MDB? How? > > > > > > > > > > > Anybody understand me? > > > > > > > > > > > Thanks you! > > > > > > > > > > We understand you. > > > > > > > > > > Read the spec to understand what is required to connect. > > > > > > > > > > However, even once you have done the hardware to be able to > > > > > > > > > connect to a > > > > > > > > > PC's RS232 port you will, more than likely run into the > > > > > > > > > problem of the 9bit > > > > > > > > > char format not being supported on a std PC serial port. > > > > > > > > > > You can fudge it using the mark/space parity control but it > > > > > > > > > is not very > > > > > > > > > nice. > > > > > > > > > > Why don't you use ccTalk instead?www.cctalk.org > > > > > > > > > > regards > > > > > > > > > PhilW > > > > > > > > > Thanks you. > > > > > > > > > I dont understand all, what is "ccTalk"?? > > > > > > > > > regards. > > > > > > > > Juanma.- Ocultar texto de la cita - > > > > > > > > > - Mostrar texto de la cita - > > > > > > > > I read a little about spec of "ccTalk", and this is other > > > > > > > protocol, > > > > > > > no? > > > > > > > > I need "to talk" with a vending machine. The standard of vending > > > > > > > machine is the MDB (i think). > > > > > > > > Are you understand me? > > > > > > > > Thanks you. > > > > > > > regards. > > > > > > > Here is a USB to MDB bridge > > > > > > :http://www.geocities.com/bonusdata/analyzer/mdb_interface/mdb_interface. > > > > > > htm > > > > > > (sorry for the spanning) > > > > > > > Here is the protocol :http://www.vending.org/technical/MDB_3.0.pdf > > > > > > >www.vending.orgiswhereyouneed to go for any info about MDC/ICP- > > > > > >Ocultar texto de la cita - > > > > > > > - Mostrar texto de la cita - > > > > > > Thanks you!! > > > > > > I know this all, but the "USB to MDB" is not a good solution for me, > > > > > should be others solutions... > > > > > > I am interesting in ccTal PhilW but i dont understand how apply this > > > > > to the vending machine. > > > > > If the vending machine does not speak CCTalk then there is no way to > > > > apply it at all, in this case. MDB/ICP is the way you will have to go. > > > > CCTalk was designed more along the lines of gaming systems and MDB was > > > > designed for vending machines and the like. Not that you couldn't use > > > > CCTalk in a vending machine, but MDB was standardized for use in them > > > > (vending machines) long ago.- Ocultar texto de la cita - > > > > > - Mostrar texto de la cita - > > > > Oh James Beck, i think that you have reason. > > > > My problem is how comunicate the pc embedded with vending machine with > > > the protocol MDB... If the unique solution the "MDB --> USB adapter"? > > > If you sum the price that a pcembedded+adapter ... for one for machine > > > is very expensive no? it must of having another solution, no? > > > > Thanks you! > > > regards. > > > Well, if you doing a one off machine, there will never be any economy of > > scale. If I were doing a single machine/test station, I wouldn't balk > > at paying the price for the adapter. If I were doing thousands of them > > I would look at doing something more task specific and cheaper. You can > > implement the protocol yourself with some kind of adapter for the PC and > > a communications library, but that would be what the specification is > > for.- Ocultar texto de la cita - > > > - Mostrar texto de la cita - > > Oh, I see that you understand me :) > > I need to create adapter for MDB to any port (serial?) the PC ... it > is difficult? I know computer science, but the electronic... :( any > idea? > > Thanks you! > regards. > > An adaptor is not an easy thing to do, simply due to the fact you need to > maintain the timing specifications of the MDB protocol. An adaptor that just > recieves a command from the PC, re-formats it for MDB and then sends it on, > waits for the response and forwards that to the PC will easily break the > timing criteria of the protocol, considering that each char takes 1mS to > transmit or receive. > > Concerning USB adaptors. Can be good providing they support, and implement > the mark/space parity support correctly. However, you still have to provide > low level coding to fudge the 9 bits via the mark/space parity. In addition > you will be required to add timing delays to ensure the parity changes are > sent over USB before transmitting the next data or parity change. We have > had success with the CP2102 from silicon Labs. It is sure however, from > experience, that supporting MDB over USB is a lot more painful than a > standard serial port. > > Another alternative is to acquire an add-on serial port that natively > supports 9 data bits at the hardware level. Not cheap, hard to find and > expensive. > > As for the vending machine implementation, you have not said, but I conclude > that YOUare building the vending machine and YOU therefore have control over > the protocol to use. Unless by some specification requirement that you use > MDB, I see no reason why you cannot use ccTalk. I believe the "protocol" is > purely for internal machine use, aimed at connecting all peripherals to a > host controller, namely your embedded PC. Any external communications is > usually by some other communications link, modem, ethernet, wifi, etc. Why > ccTalk? It's simple and most importantly can be easily supported by any PC > serial port, USB adaptor etc that supports the standard 8bit char length. It > could be any other protocol besides, that uses the 8bit data length as well. > It's just that ccTalk is well documented, well supported and widely used. > > We produce products that support both MDB and ccTalk in addition to others. > We much prefer ccTalk for its non requirement of the 9bit data format. > > regards > PhilW- Ocultar texto de la cita - > > - Mostrar texto de la cita - Oh, no, I am not a building the vending machine and I haven't control over the protocol to use, it is the problem. I need use the protocol standard in the most vending machine, that is, MDB. Do you understand me PhilW? Sorry for my English. regards.
From: PhilW on 30 Sep 2008 19:42
<juanma.freelance(a)gmail.com> wrote in message news:ef120646-80af-45a8-91c1-d53caeabeb53(a)59g2000hsb.googlegroups.com... > On 30 sep, 03:09, "PhilW" <p...(a)microcoin.com> wrote: >> <juanma.freela...(a)gmail.com> wrote in message >> >> news:73aaa712-5e75-4674-a2b2-3a62b78569a3(a)p25g2000hsf.googlegroups.com... >> On 29 sep, 20:29, James Beck <j...(a)reallykillersystems.com> wrote: >> >> >> >> >> >> > In article <29c16500-d3a1-4d46-a7d4- >> > 59492ef13...(a)w7g2000hsa.googlegroups.com>, juanma.freela...(a)gmail.com >> > says... >> >> > > On 29 sep, 17:56, James Beck <j...(a)reallykillersystems.com> wrote: >> > > > In article <3834d44e-355e-4d5f-af57-87e9ec4c0a97 >> > > > @z72g2000hsb.googlegroups.com>, juanma.freela...(a)gmail.com says... >> >> > > > > On 29 sep, 16:33, James Beck <j...(a)reallykillersystems.com> >> > > > > wrote: >> > > > > > In article <1da3a443-e530-487a-8cb7-e4166e206414 >> > > > > > @i76g2000hsf.googlegroups.com>, juanma.pal...(a)gmail.com says... >> >> > > > > > > On 29 sep, 11:11, juanma.freela...(a)gmail.com wrote: >> > > > > > > > On 29 sep, 03:32, "PhilW" <p...(a)microcoin.com> wrote: >> >> > > > > > > > > <juanma.freela...(a)gmail.com> wrote in message >> >> > > > > > > > >news:c4d5b1b0-ea81-446b-ba2a-4f7ebe2811c3(a)l64g2000hse.googlegroups.com... >> >> > > > > > > > > > Hi! >> >> > > > > > > > > > I'm sorry but I am not English and I speack English >> > > > > > > > > > very >> > > > > > > > > > bad. >> >> > > > > > > > > > My question is: How connect a PC Embedded to Vending >> > > > > > > > > > Machine? I know >> > > > > > > > > > that exist a protocol MDB that is used by vending >> > > > > > > > > > machine, >> > > > > > > > > > but this >> > > > > > > > > > conector is different to pc conector (RS232, USB, i2c, >> > > > > > > > > > etc). Can I >> > > > > > > > > > connect a PC Embedded by MDB? How? >> >> > > > > > > > > > Anybody understand me? >> >> > > > > > > > > > Thanks you! >> >> > > > > > > > > We understand you. >> >> > > > > > > > > Read the spec to understand what is required to connect. >> >> > > > > > > > > However, even once you have done the hardware to be able >> > > > > > > > > to >> > > > > > > > > connect to a >> > > > > > > > > PC's RS232 port you will, more than likely run into the >> > > > > > > > > problem of the 9bit >> > > > > > > > > char format not being supported on a std PC serial port. >> >> > > > > > > > > You can fudge it using the mark/space parity control but >> > > > > > > > > it >> > > > > > > > > is not very >> > > > > > > > > nice. >> >> > > > > > > > > Why don't you use ccTalk instead?www.cctalk.org >> >> > > > > > > > > regards >> > > > > > > > > PhilW >> >> > > > > > > > Thanks you. >> >> > > > > > > > I dont understand all, what is "ccTalk"?? >> >> > > > > > > > regards. >> > > > > > > > Juanma.- Ocultar texto de la cita - >> >> > > > > > > > - Mostrar texto de la cita - >> >> > > > > > > I read a little about spec of "ccTalk", and this is other >> > > > > > > protocol, >> > > > > > > no? >> >> > > > > > > I need "to talk" with a vending machine. The standard of >> > > > > > > vending >> > > > > > > machine is the MDB (i think). >> >> > > > > > > Are you understand me? >> >> > > > > > > Thanks you. >> > > > > > > regards. >> >> > > > > > Here is a USB to MDB bridge >> > > > > > :http://www.geocities.com/bonusdata/analyzer/mdb_interface/mdb_interface. >> > > > > > htm >> > > > > > (sorry for the spanning) >> >> > > > > > Here is the protocol >> > > > > > :http://www.vending.org/technical/MDB_3.0.pdf >> >> > > > > >www.vending.orgiswhereyouneed to go for any info about MDC/ICP- >> > > > > >Ocultar texto de la cita - >> >> > > > > > - Mostrar texto de la cita - >> >> > > > > Thanks you!! >> >> > > > > I know this all, but the "USB to MDB" is not a good solution for >> > > > > me, >> > > > > should be others solutions... >> >> > > > > I am interesting in ccTal PhilW but i dont understand how apply >> > > > > this >> > > > > to the vending machine. >> >> > > > If the vending machine does not speak CCTalk then there is no way >> > > > to >> > > > apply it at all, in this case. MDB/ICP is the way you will have to >> > > > go. >> > > > CCTalk was designed more along the lines of gaming systems and MDB >> > > > was >> > > > designed for vending machines and the like. Not that you couldn't >> > > > use >> > > > CCTalk in a vending machine, but MDB was standardized for use in >> > > > them >> > > > (vending machines) long ago.- Ocultar texto de la cita - >> >> > > > - Mostrar texto de la cita - >> >> > > Oh James Beck, i think that you have reason. >> >> > > My problem is how comunicate the pc embedded with vending machine >> > > with >> > > the protocol MDB... If the unique solution the "MDB --> USB adapter"? >> > > If you sum the price that a pcembedded+adapter ... for one for >> > > machine >> > > is very expensive no? it must of having another solution, no? >> >> > > Thanks you! >> > > regards. >> >> > Well, if you doing a one off machine, there will never be any economy >> > of >> > scale. If I were doing a single machine/test station, I wouldn't balk >> > at paying the price for the adapter. If I were doing thousands of them >> > I would look at doing something more task specific and cheaper. You can >> > implement the protocol yourself with some kind of adapter for the PC >> > and >> > a communications library, but that would be what the specification is >> > for.- Ocultar texto de la cita - >> >> > - Mostrar texto de la cita - >> >> Oh, I see that you understand me :) >> >> I need to create adapter for MDB to any port (serial?) the PC ... it >> is difficult? I know computer science, but the electronic... :( any >> idea? >> >> Thanks you! >> regards. >> >> An adaptor is not an easy thing to do, simply due to the fact you need to >> maintain the timing specifications of the MDB protocol. An adaptor that >> just >> recieves a command from the PC, re-formats it for MDB and then sends it >> on, >> waits for the response and forwards that to the PC will easily break the >> timing criteria of the protocol, considering that each char takes 1mS to >> transmit or receive. >> >> Concerning USB adaptors. Can be good providing they support, and >> implement >> the mark/space parity support correctly. However, you still have to >> provide >> low level coding to fudge the 9 bits via the mark/space parity. In >> addition >> you will be required to add timing delays to ensure the parity changes >> are >> sent over USB before transmitting the next data or parity change. We have >> had success with the CP2102 from silicon Labs. It is sure however, from >> experience, that supporting MDB over USB is a lot more painful than a >> standard serial port. >> >> Another alternative is to acquire an add-on serial port that natively >> supports 9 data bits at the hardware level. Not cheap, hard to find and >> expensive. >> >> As for the vending machine implementation, you have not said, but I >> conclude >> that YOUare building the vending machine and YOU therefore have control >> over >> the protocol to use. Unless by some specification requirement that you >> use >> MDB, I see no reason why you cannot use ccTalk. I believe the "protocol" >> is >> purely for internal machine use, aimed at connecting all peripherals to a >> host controller, namely your embedded PC. Any external communications is >> usually by some other communications link, modem, ethernet, wifi, etc. >> Why >> ccTalk? It's simple and most importantly can be easily supported by any >> PC >> serial port, USB adaptor etc that supports the standard 8bit char length. >> It >> could be any other protocol besides, that uses the 8bit data length as >> well. >> It's just that ccTalk is well documented, well supported and widely used. >> >> We produce products that support both MDB and ccTalk in addition to >> others. >> We much prefer ccTalk for its non requirement of the 9bit data format. >> >> regards >> PhilW- Ocultar texto de la cita - >> >> - Mostrar texto de la cita - > > Oh, no, I am not a building the vending machine and I haven't control > over the protocol to use, it is the problem. I need use the protocol > standard in the most vending machine, that is, MDB. > > Do you understand me PhilW? Sorry for my English. > > regards. Ok, then you have no choice but to write low level code to fudge the 9bit char by using the mark/space parity control. You do this by programming the UART 8bit with parity, that makes the 9 bits. The parity you program to be manually controlled using the mark/space controls to simulate the ninth bit. When you sent the first byte of the message, you first make parity to be Mark, this makes effective 9th bit set = address byte. Send the address byte. You then make parity to be Space for remainder of message = 9th bit clear. To receive a reply just set to space parity and look for parity error for end of message. Since this is a fudge you will be at risk to miss-interpreting a real parity error, but that is the consequences of not having full 9 bit support in hardware. Anyhow good luck. It can be done, I know because we support it. It's just not an ideal solution. Until you really know what you doing in it's implementation, stay away from virtual serial ports over USB because they do not act the same as a standard serial port. They move data in blocks and will not maintain the parity manipulation synchronously with the data bytes. They will need delays to allow the control commands to transfer before sending the data etc. This will slow down your effective data rate under MDB. Also you should make an investment in a good serial coms monitor tool, that can capture and timestamp every event on the link between the host and the device. It will pay for itself easily in the time you save discovering what is really happening in the transfer. We used a tool called "ViewComm Async" from www.greenleafsoft.com. Such a tool is worth it's weight in gold. regards PhilW |