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Help needed please - Serial connection using laptop

PostPosted: Wed Jun 08, 2011 7:22 pm
by bri_tal
I have made up a satisfactory serial lead and can telnet tivo, using my pc's wired ethernet and Ubuntu. However my main tivo is in the lounge, wheras my pc is upstairs and so I bought a usb to serial cable+serial female/female gender changer, so that I could try to connect to tivo from my laptop's usb port.

The usb-serial adapter driver installed correctly and the device manager in windows, sees it as com 4. However, repeating the steps that were successful when the serial lead was connected to com 1 of the pc, I cannot get telnet to work from the laptop. I also tried the laptop arrangement using Ubuntu but I do not kwow how to tell if the usb-serial driver was installed.

Does anyone have any ideas please?

Re: Help needed please - Serial connection using laptop

PostPosted: Wed Jun 08, 2011 7:35 pm
by poppadum
There are a few hoops to jump through to set Windows up to receive an incoming serial ppp connection. For Windows XP, this page has some good instructions.

Re: Help needed please - Serial connection using laptop

PostPosted: Wed Jun 08, 2011 7:40 pm
by bri_tal
Thanks poppadum but I used those instructions and they do not cover my situation (wireless laptop serial connection)

Re: Help needed please - Serial connection using laptop

PostPosted: Wed Jun 08, 2011 7:48 pm
by poppadum
bri_tal wrote:Thanks poppadum but I used those instructions and they do not cover my situation (wireless laptop serial connection)

Strange, the fact that the laptop connects to the Internet via a wireless connection shouldn't make any difference (that's how i did it). Is Windows showing an incoming PPP connection in control panel -> network connections?

I thought there was another post somewhere with instructions and I've now found it: here it is. Bear in mind that many of the tivo-side changes recommended in that thread have now been included in later versions of the altepg image.

Re: Help needed please - Serial connection using laptop

PostPosted: Wed Jun 08, 2011 7:59 pm
by gcobb
I have had variable results using a USB-to-serial connector. You might want to check out that that is working properly (for example, using a terminal program on the PC). I assume you have set up the Tivo to automatically run PPP on the serial port when it boots, so there are two ways to get real text access to check the connection is working properly:

  • Plug the cable in and run a terminal emulator on the PC set up for 9600 8N1. Then reboot the Tivo. As it reboots, hit <Return> several times on the PC and see if you can get a password prompt. If so, enter the password "factory" and look at the menu of commands. Don't change anything but try to convince yourself it is looking OK -- get the menu to redisplay a few times, etc.
  • Plug back into your other PC so telnet works. Then change the rc.sysinit so it won't run PPP on the next boot but will run bash instead (google for instructions on how to run bash on the tivo serial port if you don't know already). Then reboot and plug the serial cable into your laptop and start a terminal emulator set up for 9600 8N1. You can then do a few commands (as if you were telneted in) to check it is working (start with the command "stty sane" so you get echo working). You will need to use the bash session to re-setup PPP.

If that is working OK then the problem may be something more subtle such as modem control or line speed (although I am surprised it would work any differently using the USB connection instead of a direct connection).

Re: Help needed please - Serial connection using laptop

PostPosted: Wed Jun 08, 2011 10:25 pm
by DX30
I too had some trouble when first using a wifi laptop. One thing I found was the USB - serial converter I used wouldn't connect at 115200. A different converter was OK at that speed so if you have more than 1 try changing it, or lowering the speed.

The other problems I hit were to do with Vista so not really applicable here but I include them in case they help someone else.

First with Vista using DHCP for the connection didn't work (unlike XP) so I had to manually configure IP addresses.

The second issue was I couldn't get my McAfee firewall to play nice so I reverted to the inbuilt Microsoft firewall.

Re: Help needed please - Serial connection using laptop

PostPosted: Thu Jun 09, 2011 9:39 am
by bri_tal
poppadum wrote:
bri_tal wrote:Thanks poppadum but I used those instructions and they do not cover my situation (wireless laptop serial connection)

Strange, the fact that the laptop connects to the Internet via a wireless connection shouldn't make any difference (that's how i did it). Is Windows showing an incoming PPP connection in control panel -> network connections?


Control panel shows the icon for incoming connection but it doesnt seem to be active. Anyway, I've given-up on a windows solution and am now concentrating my efforts on ubuntu - If only I could identify what the system sees the port as, so that I can suitably amend the /etc/init.d/RC.local file.

Thanks for your help

Re: Help needed please - Serial connection using laptop

PostPosted: Thu Jun 09, 2011 9:44 am
by bri_tal
gcobb wrote:I have had variable results using a USB-to-serial connector. You might want to check out that that is working properly (for example, using a terminal program on the PC). I assume you have set up the Tivo to automatically run PPP on the serial port when it boots, so there are two ways to get real text access to check the connection is working properly:

  • Plug the cable in and run a terminal emulator on the PC set up for 9600 8N1. Then reboot the Tivo. As it reboots, hit <Return> several times on the PC and see if you can get a password prompt. If so, enter the password "factory" and look at the menu of commands. Don't change anything but try to convince yourself it is looking OK -- get the menu to redisplay a few times, etc.
  • Plug back into your other PC so telnet works. Then change the rc.sysinit so it won't run PPP on the next boot but will run bash instead (google for instructions on how to run bash on the tivo serial port if you don't know already). Then reboot and plug the serial cable into your laptop and start a terminal emulator set up for 9600 8N1. You can then do a few commands (as if you were telneted in) to check it is working (start with the command "stty sane" so you get echo working). You will need to use the bash session to re-setup PPP.

If that is working OK then the problem may be something more subtle such as modem control or line speed (although I am surprised it would work any differently using the USB connection instead of a direct connection).


Tried Hyperterminal on the PC, using usb-serial and a connection to tivo was made. Could'nt telnet though. Will check to see if the same applies with the laptop on the other machine.

Thanks for your help.

Re: Help needed please - Serial connection using laptop

PostPosted: Thu Jun 09, 2011 2:24 pm
by spitfires
Are you using an AltEPG image? Early version (don't about current one) of AltEPG enabled PPP on the serial by default and I don't think you can run telnet-to-bash-on-serial at the same time as PPP-on-serial (although I could be wrong).

Re: Help needed please - Serial connection using laptop

PostPosted: Fri Jun 10, 2011 9:31 am
by bri_tal
spitfires wrote:Are you using an AltEPG image? Early version (don't about current one) of AltEPG enabled PPP on the serial by default and I don't think you can run telnet-to-bash-on-serial at the same time as PPP-on-serial (although I could be wrong).


No. that is not the problem. It's a case of the adapter not being recognized in the tivo software. Ubuntu loads the driver ok and assigns the device as ttyUSB0 (USB zero) So I thought it would be necessary to amend the /etc/init.d/rc.local file, replacing ttyS0 with ttyUSB but I was still unable to telnet.

Connecting the unmodified serial cable, however, between my PC and tivo, does enable me to telnet.

I am pretty certain that the usb-serial adapter is OK, (others have had success with the same product) so I must be missing something simple. I can get a connection using windows Hyperterminal.

Re: Help needed please - Serial connection using laptop

PostPosted: Fri Jun 10, 2011 10:36 am
by JDW
Trouble with a USB to serial adaptor hit me last week. If it uses a Prolific PL2302 Chip - and your system will tell you that - there is a new driver on the prolific website which alters some timeouts. I found that the new version v1417 instantly fixed my connection issue for a GPS I use.

Re: Help needed please - Serial connection using laptop

PostPosted: Fri Jun 10, 2011 4:59 pm
by bri_tal
JDW wrote:Trouble with a USB to serial adaptor hit me last week. If it uses a Prolific PL2302 Chip - and your system will tell you that - there is a new driver on the prolific website which alters some timeouts. I found that the new version v1417 instantly fixed my connection issue for a GPS I use.


Mine is a prolific PL2303. No problems with the driver, according to system data. I might experiment with different connection speeds.

Re: Help needed please - Serial connection using laptop

PostPosted: Mon Jun 13, 2011 8:35 pm
by bri_tal
Well, tried everything to get the adapter to work, but no joy.

In the end, I opted for extending the original serial lead, using cat5 cable (2 twisted pairs) and trailing it downstairs into the lounge. This works a treat but obviously does not please my better half, so I only intend to do this once every week, to update programme guide data.