Modem speed

  • Thread starter Thread starter terry
  • Start date Start date
T

terry

I have a delphi program which uses modem component to connect from PC
side modem to a device side modem. I find that the program does not
work with some kind of modems. (Some other kind of modems works very
stable!)

After connection my program will change the connection speed 19200
down to 9600. However, I find that when I do this, the connection
terminates.

Do anyone know why some kinds of modem will terminate the connection
when I change speed and how to solve it?

Because I cannot control which modem my client will use so that my
program needs to work with different kinds of modems!

Thanks!
 
terry said:
I have a delphi program which uses modem component to connect from PC
side modem to a device side modem. I find that the program does not
work with some kind of modems. (Some other kind of modems works very
stable!)

After connection my program will change the connection speed 19200
down to 9600. However, I find that when I do this, the connection
terminates.

Do anyone know why some kinds of modem will terminate the connection
when I change speed and how to solve it?

Because I cannot control which modem my client will use so that my
program needs to work with different kinds of modems!

Thanks!
Click to expand...
 
terry said:
I have a delphi program which uses modem component to connect from PC
side modem to a device side modem. I find that the program does not
work with some kind of modems. (Some other kind of modems works very
stable!)

After connection my program will change the connection speed 19200
down to 9600. However, I find that when I do this, the connection
terminates.

Do anyone know why some kinds of modem will terminate the connection
when I change speed and how to solve it?

Because I cannot control which modem my client will use so that my
program needs to work with different kinds of modems!

Thanks!
Click to expand...
 
terry said:
I have a delphi program which uses modem component to connect from PC
side modem to a device side modem. I find that the program does not
work with some kind of modems. (Some other kind of modems works very
stable!)

After connection my program will change the connection speed 19200
down to 9600. However, I find that when I do this, the connection
terminates.

Do anyone know why some kinds of modem will terminate the connection
when I change speed and how to solve it?
Click to expand...


Probably it's the software modems that do this. Not sure if there is a
solution. These same modems are the ones that drop their internet
connection if the connection isn't great. There may be a generic AT commend
that will limit the modem speed on connection so you don't have to lower it
later?


http://www.engplanet.com/content/Modem.html
 
: terry wrote:
:
: > I have a delphi program which uses modem component to connect from PC
: > side modem to a device side modem. I find that the program does not
: > work with some kind of modems. (Some other kind of modems works very
: > stable!)
: >
: > After connection my program will change the connection speed 19200
: > down to 9600. However, I find that when I do this, the connection
: > terminates.
: >
: > Do anyone know why some kinds of modem will terminate the connection
: > when I change speed and how to solve it?
: >
:
:
: Probably it's the software modems that do this. Not sure if there is a
: solution. These same modems are the ones that drop their internet
: connection if the connection isn't great. There may be a generic AT
commend
: that will limit the modem speed on connection so you don't have to lower
it
: later?
:
:
: http://www.engplanet.com/content/Modem.html
: --
:
: Stacey

Unless you're using ancient modems most maodems "train" to a speed that is
acceptable to both parties, even the software ones. Try setting your modem
at 115200kb and see what happens.It should train automatically.

claus
 
santa said:
: terry wrote:
:
: > I have a delphi program which uses modem component to connect from PC
: > side modem to a device side modem. I find that the program does not
: > work with some kind of modems. (Some other kind of modems works very
: > stable!)
: >
: > After connection my program will change the connection speed 19200
: > down to 9600. However, I find that when I do this, the connection
: > terminates.
: >
: > Do anyone know why some kinds of modem will terminate the connection
: > when I change speed and how to solve it?
: >
:
:
: Probably it's the software modems that do this. Not sure if there is a
: solution. These same modems are the ones that drop their internet
: connection if the connection isn't great. There may be a generic AT
commend
: that will limit the modem speed on connection so you don't have to lower
it
: later?
:
:
: http://www.engplanet.com/content/Modem.html
: --
:
: Stacey

Unless you're using ancient modems most maodems "train" to a speed that is
acceptable to both parties, even the software ones. Try setting your modem
at 115200kb and see what happens.It should train automatically.

claus
Click to expand...


I think their problem is the software tries to =switch= the speed lower and
when it does, some modems drop the connection. Very few newer "software"
modems allow for variable speeds once they connect and once they've done
the handshake and set the connection speed, that's it. I was thinking they
might be able to =force= the modem to connect at 9600 right off the bat
rather than trying to switch it to that speed after it connects to avoid
dropping the connection.
 
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