I have an i686 mono core system configured as a CentOS-5.2 server. It has one DB9P RS-232 serial connector and six USB connectors. The DB9p is configuered as STTY0 for the attached MultiTec MT5638ZBA fax modem. I would very much like to connect my MS WindowsXPpro laptop, which only has USB connectors, to this server via telnet or ssh over a direct connection.
Is there a way to connect / configure a comm port to a raw USB port in windows / centos and to use a direct cable connection between the two? Or, is a usb to serial converter device required at both ends?
I expect to use either puTTY or hyperterm as the windows client. What I need to know is:
Is this is even possible?
How do you configure the tty ports on CentOS for this to work?
How do you configure the comm port on MS-WinXPpro?
What cable does one require?
I have never had this problem before since all our hosts have previously come equipped with two serial ports. However, the next generation machines apparently have no RS-232 serial ports at all, just six usb ports. So, this problem might as well be faced now as later, when it is unavoidable.
Regards,
on 7-30-2008 12:14 PM James B. Byrne spake the following:
I have an i686 mono core system configured as a CentOS-5.2 server. It has one DB9P RS-232 serial connector and six USB connectors. The DB9p is configuered as STTY0 for the attached MultiTec MT5638ZBA fax modem. I would very much like to connect my MS WindowsXPpro laptop, which only has USB connectors, to this server via telnet or ssh over a direct connection.
Is there a way to connect / configure a comm port to a raw USB port in windows / centos and to use a direct cable connection between the two? Or, is a usb to serial converter device required at both ends?
I expect to use either puTTY or hyperterm as the windows client. What I need to know is:
Is this is even possible?
I think you will need 2 usb to serial convertors, one on the server and one on the laptop. The server will have to be set to redirect over the serial port, as it will not be telnet or ssh. Not all servers will redirect their early screens over a serial port, but grub, lilo, and the kernel can send their output over a serial port.
How do you configure the tty ports on CentOS for this to work?
The usb to serial adapter should be seen by the server and will be given a ttyS of its own.
How do you configure the comm port on MS-WinXPpro?
The adapter will get a virtual com port assigned by windows plug and play. This is how my laptop is. No serial ports, just a serial to usb adapter that I keep attached to the null-modem cable in my bag.
What cable does one require?
A serial crossover or "null-modem" cable.
I have never had this problem before since all our hosts have previously come equipped with two serial ports. However, the next generation machines apparently have no RS-232 serial ports at all, just six usb ports. So, this problem might as well be faced now as later, when it is unavoidable.
It must not be a true server system, as all good servers have some sort of out-of-band management available for headless systems.
James B. Byrne wrote:
I have an i686 mono core system configured as a CentOS-5.2 server. It has one DB9P RS-232 serial connector and six USB connectors. The DB9p is configuered as STTY0 for the attached MultiTec MT5638ZBA fax modem. I would very much like to connect my MS WindowsXPpro laptop, which only has USB connectors, to this server via telnet or ssh over a direct connection.
Is there a way to connect / configure a comm port to a raw USB port in windows / centos and to use a direct cable connection between the two? Or, is a usb to serial converter device required at both ends?
I expect to use either puTTY or hyperterm as the windows client. What I need to know is:
Is this is even possible?
How do you configure the tty ports on CentOS for this to work?
How do you configure the comm port on MS-WinXPpro?
What cable does one require?
I have never had this problem before since all our hosts have previously come equipped with two serial ports. However, the next generation machines apparently have no RS-232 serial ports at all, just six usb ports. So, this problem might as well be faced now as later, when it is unavoidable.
I can't imagine why anyone would want to do this on any system capable of using a network connection instead. You can get usb cables that are really back-to-back usb<->100BaseT adapters and they are popular now because Windows/Vista knows how to migrate things from an XP box with them but it is still a fairly dumb concept if a real NIC is a possibility on at least one of the ends. The reason you don't see much about this kind of scenario any more is that most people would have a cheap home inernet router that would provide the network interconnect and act as a DHCP server to take care of the setup automatically. If you don't have/want one of those, a crossover ethernet cable will work with one, both, or neither NIC being a USB adapter and you can easily hand-configure the addresses.
On Wed, July 30, 2008 15:14, James B. Byrne wrote:
I have an i686 mono core system configured as a CentOS-5.2 server. It has one DB9P RS-232 serial connector and six USB connectors. The DB9p is configured as STTY0 for the attached MultiTec MT5638ZBA fax modem. I would very much like to connect my MS WindowsXPpro laptop, which only has USB connectors, to this server via telnet or ssh over a direct connection.
On Wed Jul 30 20:19:44 UTC 2008, Les Mikesell lesmikesell at gmail.com wrote:
I can't imagine why anyone would want to do this on any system capable of using a network connection instead.
The availability of the nic cannot be guaranteed since the machine is being configured on one netblock and then being physically transferred to a distant location. It is entirely possible that whatever IP address is assigned to the eth0 connection here as being the one that will be used there may not actually work on the target network. The purpose of the serial connection is to permit a laptop to substitute for a monitor/kb/mouse on site in that eventuality. If it proves too cumbersome to enable direct host to host communications via usb then we will simply ship a 15" flat screen, kb and mouse with the unit and have them returned afterwards.
We could, I suppose, reconfigure the available serial port as a tty and then connect that way, establish network connectivity, detach, and reconfigure the DB9p as an STTY for the fax service.
Thank you for the cable suggestion. I will look into that.
Regards,
James B. Byrne wrote:
On Wed, July 30, 2008 15:14, James B. Byrne wrote:
I have an i686 mono core system configured as a CentOS-5.2 server. It has one DB9P RS-232 serial connector and six USB connectors. The DB9p is configured as STTY0 for the attached MultiTec MT5638ZBA fax modem. I would very much like to connect my MS WindowsXPpro laptop, which only has USB connectors, to this server via telnet or ssh over a direct connection.
On Wed Jul 30 20:19:44 UTC 2008, Les Mikesell lesmikesell at gmail.com wrote:
I can't imagine why anyone would want to do this on any system capable of using a network connection instead.
The availability of the nic cannot be guaranteed since the machine is being configured on one netblock and then being physically transferred to a distant location. It is entirely possible that whatever IP address is assigned to the eth0 connection here as being the one that will be used there may not actually work on the target network. The purpose of the serial connection is to permit a laptop to substitute for a monitor/kb/mouse on site in that eventuality. If it proves too cumbersome to enable direct host to host communications via usb then we will simply ship a 15" flat screen, kb and mouse with the unit and have them returned afterwards.
If you are confident that the server itself would be up and functional, you could configure an extra NIC with a private subnet that offers DHCP so a laptop plugged in with a crossover cable would be able to connect to a known address. It might even be possible to make that happen after a USB adapter is plugged in.
We could, I suppose, reconfigure the available serial port as a tty and then connect that way, establish network connectivity, detach, and reconfigure the DB9p as an STTY for the fax service.
Can't you just run one of the getty's that know how to start both fax and data services on the fax modem and either swap cables or dial it up if you need to log in on the serial port? I thought both hylafax and sendfax/vgetty could do that.
James B. Byrne wrote:
... The purpose of the serial connection is to permit a laptop to substitute for a monitor/kb/mouse on site in that eventuality. If it proves too cumbersome to enable direct host to host communications via usb then we will simply ship a 15" flat screen, kb and mouse with the unit and have them returned afterwards.
or, use commercial servers with integrated TCP kvm's such as HP's iLO, Dell's DRAC, Sun's ILOM, etc. These provide virtual consoles and CD/DVD's over IP where the client side just needs a java enabled web browser. they generally have their own ethernet ports for this, and you assign them a dedicated IP address. most require SSL (https:) to connect, so are quite secure.
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James B. Byrne -
John R Pierce -
Les Mikesell -
Scott Silva