From Andrey.Bakhmat at fairwaves.ru Mon Dec 3 12:11:51 2012 From: Andrey.Bakhmat at fairwaves.ru (Andrey Bakhmat) Date: Mon, 3 Dec 2012 16:11:51 +0400 Subject: Open-source telecom t-shirts In-Reply-To: References: <50833575.6060502@andreicostin.com> Message-ID: Hello folks, After several weeks of persistent struggle the winner of voting is "We are open 24/7". We decided to put this motto on the back of the T-shirts to avoid overloading the front side by text. We have slightly changed the graphic design - see the final version in the attached file. It will be available in vector format so you could use it as you wish. On Thu, Nov 8, 2012 at 8:55 AM, Andrey Bakhmat wrote: > Hello all, > > We've been waiting patiently for new ideas for last tree weeks. Now it's > time to vote. Choose or loose! > > Below is the link to our slogan survey. > > https://docs.google.com/spreadsheet/viewform?formkey=dFFnWmdYUGczdnQ5Ny1KWWdHa1ZleVE6MQ#gid=0 > Please let me know if this link doesn't work for you. > > > > On Mon, Oct 22, 2012 at 3:29 PM, Andrey Bakhmat < > Andrey.Bakhmat at fairwaves.ru> wrote: > >> Hello all, >> >> We are preparing for voting now and trying to use proposed slogans as >> they were written. The only exception is the term "Open Telecom", we >> convert it into "Open-Source Telecom". >> >> "Open" is a very general abstract concept, while "Open-source" - very >> specific. For example, Open Telecom could mean so-called "Open Standards", >> so GSM, 3G, and LTE become Open Telecom in that sense. >> >> >> >> >> On Sun, Oct 21, 2012 at 3:36 AM, Lists proxy (A.C.) < >> lists at andreicostin.com> wrote: >> >>> Hello all/list, >>> >>> My humble versions/variations. >>> >>> Perhaps a variation on the "Telecom wants to be FREE" slogan could be >>> "Fairwaves - we are OPEN 24/7" or "OpenTelecom - we are OPEN 24/7" >>> >>> Cheers, >>> Andrei >>> >>> >>> On 20/10/2012 16:35, Andrey Bakhmat wrote: >>> >>> Golden gear and green SIM-card version >>> >>> On Sat, Oct 20, 2012 at 2:50 PM, Andrey Sviyazov >> > wrote: >>> >>>> Ok. If you guys really sure then I agree. >>>> I just said my doubt. >>>> >>>> Best regards, >>>> Andrey Sviyazov. >>>> (Sent from my mobile client) >>>> 20.10.2012 14:23 ???????????? "Andrey Bakhmat" < >>>> Andrey.Bakhmat at fairwaves.ru> ???????: >>>> >>>> Alexander was right, I choose blule color to hint at Fariwaves. >>>>> >>>>> On Sat, Oct 20, 2012 at 2:12 PM, Andrey Sviyazov < >>>>> andreysviyaz at gmail.com> wrote: >>>>> >>>>>> Hmm, I missed it. >>>>>> But really not sure that Fairwaves will associated to the blue colors >>>>>> (and vice versa) due to the blue logo. >>>>>> It doesn't mean that all around must be in blue. >>>>>> >>>>>> Best regards, >>>>>> Andrey Sviyazov. >>>>>> (Sent from my mobile client) >>>>>> 20.10.2012 13:43 ???????????? "Alexander Chemeris" < >>>>>> alexander.chemeris at gmail.com> ???????: >>>>>> >>>>>> Because blue is the Fairwaves color :) >>>>>>> >>>>>>> On Sat, Oct 20, 2012 at 1:42 PM, Andrey Sviyazov < >>>>>>> andreysviyaz at gmail.com> wrote: >>>>>>> > And about colors - why blue? >>>>>>> > On my opinion, dark green and golden contacts looks better. >>>>>>> > At least blue and gold is not good combination for me. >>>>>>> > It looks like church painting. >>>>>>> > >>>>>>> > Best regards, >>>>>>> > Andrey Sviyazov. >>>>>>> > (Sent from my mobile client) >>>>>>> > >>>>>>> > 20.10.2012 13:32 ???????????? "Andrey Sviyazov" < >>>>>>> andreysviyaz at gmail.com> >>>>>>> > ???????: >>>>>>> > >>>>>>> >> Andrey. >>>>>>> >> You could add HARDWARE word, to align text with vertical Sim. >>>>>>> >> >>>>>>> >> Best regards, >>>>>>> >> Andrey Sviyazov. >>>>>>> >> (Sent from my mobile client) >>>>>>> >> >>>>>>> >> 20.10.2012 13:01 ???????????? "Andrey Bakhmat" >>>>>>> >> ???????: >>>>>>> >>> >>>>>>> >>> I suggest "Unlock communications for the rest of us!" - just >>>>>>> another >>>>>>> >>> option bring to a vote. >>>>>>> >>> Vertical SIM looks good, but it was difficult for me to arrange >>>>>>> it with >>>>>>> >>> the text. If somebody wants to play with it, I can provide >>>>>>> vector (AI) >>>>>>> >>> files. >>>>>>> >>> Superman style - good idea, previous versions of T-shirt was >>>>>>> slightly >>>>>>> >>> boring. So I propose make something informal at the back side. >>>>>>> >>> >>>>>>> >>> On Sat, Oct 20, 2012 at 1:03 AM, Sylvain Munaut < >>>>>>> 246tnt at gmail.com> wrote: >>>>>>> >>>> >>>>>>> >>>> >> I like "Telecom wants to be free" slogan more, but that's >>>>>>> just me. >>>>>>> >>>> >>>>>>> >>>> > "Telecom Wants to be Open"? >>>>>>> >>>> >>>>>>> >>>> I prefer "Telecom wants to be Free" too. (upper case F) >>>>>>> >>>> >>>>>>> >>>> and I also prefer the sim to be vertical. >>>>>>> >>>> >>>>>>> >>>> >>>>>>> >>>> Just my 2c >>>>>>> >>>> >>>>>>> >>>> Cheers, >>>>>>> >>>> >>>>>>> >>>> Sylvain >>>>>>> >>> >>>>>>> >>> >>>>>>> >>>>>> >>> >> >> >> -- >> Best regards, >> Andrey Bakhmat >> COO, Fairwaves LLC >> http://fairwaves.ru >> > > > > -- > Best regards, > Andrey Bakhmat > COO, Fairwaves LLC > http://fairwaves.ru > -- Best regards, Andrey Bakhmat COO, Fairwaves LLC http://fairwaves.ru -------------- next part -------------- An HTML attachment was scrubbed... URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: Open-source T-shirt final.png Type: image/png Size: 251393 bytes Desc: not available URL: From tom at tsou.cc Thu Dec 6 03:13:55 2012 From: tom at tsou.cc (Thomas Tsou) Date: Wed, 5 Dec 2012 22:13:55 -0500 Subject: Burst start/end phase error Message-ID: Hi Alexander, Please try the last commit at git://github.com/ttsou/openbts-p2.8.git laurent I tested with 4 samples per symbol as we did in the past. Reducing the start/end phase error involved adding bits so that there is no partial phase transition to/from nothing. We then zero out the excess bits with a simple power mask. Thomas From alexander.chemeris at gmail.com Thu Dec 6 03:55:27 2012 From: alexander.chemeris at gmail.com (Alexander Chemeris) Date: Thu, 6 Dec 2012 07:55:27 +0400 Subject: Burst start/end phase error In-Reply-To: References: Message-ID: Thanks Thomas, I'll try this. Did you test receive side with this patch? On Thu, Dec 6, 2012 at 7:13 AM, Thomas Tsou wrote: > Hi Alexander, > > Please try the last commit at > > git://github.com/ttsou/openbts-p2.8.git laurent > > I tested with 4 samples per symbol as we did in the past. Reducing the > start/end phase error involved adding bits so that there is no partial > phase transition to/from nothing. We then zero out the excess bits > with a simple power mask. > > Thomas -- Regards, Alexander Chemeris. CEO, Fairwaves LLC / ??? ??????? http://fairwaves.ru From thomastsou at gmail.com Thu Dec 6 04:55:30 2012 From: thomastsou at gmail.com (Thomas Tsou) Date: Wed, 5 Dec 2012 23:55:30 -0500 Subject: Burst start/end phase error In-Reply-To: References: Message-ID: On Wed, Dec 5, 2012 at 10:55 PM, Alexander Chemeris wrote: > Thanks Thomas, I'll try this. > > Did you test receive side with this patch? No, the E4406 was plugged in the entire time. Thomas From alexander.chemeris at gmail.com Thu Dec 6 05:48:47 2012 From: alexander.chemeris at gmail.com (Alexander Chemeris) Date: Thu, 6 Dec 2012 09:48:47 +0400 Subject: Burst start/end phase error In-Reply-To: References: Message-ID: On Thu, Dec 6, 2012 at 8:55 AM, Thomas Tsou wrote: > On Wed, Dec 5, 2012 at 10:55 PM, Alexander Chemeris > wrote: >> Thanks Thomas, I'll try this. >> >> Did you test receive side with this patch? > > No, the E4406 was plugged in the entire time. Got it. Waiting for the receive side test. -- Regards, Alexander Chemeris. CEO, Fairwaves LLC / ??? ??????? http://fairwaves.ru From tom at tsou.cc Fri Dec 7 08:28:55 2012 From: tom at tsou.cc (Thomas Tsou) Date: Fri, 7 Dec 2012 03:28:55 -0500 Subject: Burst start/end phase error In-Reply-To: References: Message-ID: On Wed, Dec 5, 2012 at 10:13 PM, Thomas Tsou wrote: > Please try the last commit at > > git://github.com/ttsou/openbts-p2.8.git laurent > > I tested with 4 samples per symbol as we did in the past. Reducing the > start/end phase error involved adding bits so that there is no partial > phase transition to/from nothing. We then zero out the excess bits > with a simple power mask. It turns out that the transmit tester likes this signal, but my handsets do not; they do not even recognize it. Perhaps this form of testing is not as reliable as I thought. So I reverted the commit to handle start/end phase errors. I also setup the correlators with single pulse (I see no benefit for the more complicated modulator on receive), and set timing for 4sps. I receive RA and normal bursts fine. The start/end transients will need to be handled a different way. Thomas From alexander.chemeris at gmail.com Thu Dec 13 14:04:41 2012 From: alexander.chemeris at gmail.com (Alexander Chemeris) Date: Thu, 13 Dec 2012 18:04:41 +0400 Subject: Burst start/end phase error In-Reply-To: References: Message-ID: On Fri, Dec 7, 2012 at 12:28 PM, Thomas Tsou wrote: > On Wed, Dec 5, 2012 at 10:13 PM, Thomas Tsou wrote: >> Please try the last commit at >> >> git://github.com/ttsou/openbts-p2.8.git laurent >> >> I tested with 4 samples per symbol as we did in the past. Reducing the >> start/end phase error involved adding bits so that there is no partial >> phase transition to/from nothing. We then zero out the excess bits >> with a simple power mask. > > It turns out that the transmit tester likes this signal, but my > handsets do not; they do not even recognize it. Perhaps this form of > testing is not as reliable as I thought. > > So I reverted the commit to handle start/end phase errors. I also > setup the correlators with single pulse (I see no benefit for the more > complicated modulator on receive), and set timing for 4sps. I receive > RA and normal bursts fine. The start/end transients will need to be > handled a different way. Ok, we've tested 'laurent' branch and it works great for both Rx and Tx, thanks! Have you had any success with fixing ramp up / ramp down issue? -- Regards, Alexander Chemeris. CEO, Fairwaves LLC / ??? ??????? http://fairwaves.ru From tom at tsou.cc Fri Dec 14 03:10:44 2012 From: tom at tsou.cc (Thomas Tsou) Date: Thu, 13 Dec 2012 22:10:44 -0500 Subject: Burst start/end phase error In-Reply-To: References: Message-ID: On Thu, Dec 13, 2012 at 9:04 AM, Alexander Chemeris wrote: > Ok, we've tested 'laurent' branch and it works great for both Rx and Tx, thanks! > > Have you had any success with fixing ramp up / ramp down issue? No, not yet. I tried some other combinations that worked fine on the signal tester, but the handset still wasn't happy. I'm not yet sure why. Thomas From alexander.chemeris at gmail.com Fri Dec 14 04:16:19 2012 From: alexander.chemeris at gmail.com (Alexander Chemeris) Date: Fri, 14 Dec 2012 08:16:19 +0400 Subject: Burst start/end phase error In-Reply-To: References: Message-ID: On Fri, Dec 14, 2012 at 7:10 AM, Thomas Tsou wrote: > On Thu, Dec 13, 2012 at 9:04 AM, Alexander Chemeris > wrote: >> Ok, we've tested 'laurent' branch and it works great for both Rx and Tx, thanks! >> >> Have you had any success with fixing ramp up / ramp down issue? > > No, not yet. I tried some other combinations that worked fine on the > signal tester, but the handset still wasn't happy. I'm not yet sure > why. Did you check power mask with the signal tester, or phase error too? May be differential modulation is somehow broken by this change? -- Regards, Alexander Chemeris. CEO, Fairwaves LLC / ??? ??????? http://fairwaves.ru From tom at tsou.cc Fri Dec 14 04:52:42 2012 From: tom at tsou.cc (Thomas Tsou) Date: Thu, 13 Dec 2012 23:52:42 -0500 Subject: Burst start/end phase error In-Reply-To: References: Message-ID: On Thu, Dec 13, 2012 at 11:16 PM, Alexander Chemeris wrote: >> No, not yet. I tried some other combinations that worked fine on the >> signal tester, but the handset still wasn't happy. I'm not yet sure >> why. > > Did you check power mask with the signal tester, or phase error too? > May be differential modulation is somehow broken by this change? The modified case I measured earlier was improved in power mask and phase error, but just failed in real testing. There is an overall phase rotation from the added bits, but this technically shouldn't matter - and adding only the trailing bits also caused the failure condition. My guess is that this is ramp/power related and not directly due to modulation. My power shaping profile was really a coarse guesstimate, so that may be a factor. But I'm surprised it doesn't work because having no power profile seems to work quite well (without the extra bits). Thomas From alexander.chemeris at gmail.com Sat Dec 15 14:37:55 2012 From: alexander.chemeris at gmail.com (Alexander Chemeris) Date: Sat, 15 Dec 2012 18:37:55 +0400 Subject: UmTRX beta aka Limited Edition sales start! Message-ID: Dear all, We want to make a Christmas gift for the community and it's my pleasure to announce the start of sales of UmTRXv2 beta samples aka Limited Edition. What is UmTRX? ============== UmTRX is an SDR transceiver, which we, Fairwaves, developed specifically for OpenBTS. It's similar to USRPs, but is heavily modified to be the best hardware for OpenBTS. More details are available at the project web-site: https://code.google.com/p/umtrx/ Ordering and Shipping ===================== To claim your UmTRXv2 Limited Edition, please fill in this form: https://docs.google.com/spreadsheet/viewform?formkey=dGVHNlNDaXVoSHp2eC1EcVFPcXFXLWc6MQ You will receive a payment link shortly after we receive your answer. The shipping cost will be estimated when we have everything ready for shipping, we'll contact you again by then. There are only 14 units in this Limited Edition batch, so we allow you to claim only 1 or 2 units. The base price for a UmTRX is $1500 just as we promised. Since we are relying on your support to fund further development, we encourage you to donate an additional amount. You donations are critical for us to produce the best ever hardware for OpenBTS. The 5 highest pledgers will become the proud owners of UmTRX Serial Numbers 1 through 5 and will be recognized on the UmTRX project site. Shipping will be from Paris, France with FedEx or some other express carrier. We plan to ship as soon as we receive orders for all 14 units, so the shipping date is not fixed yet. We'll contact you when we fix it. What does "beta" mean? ====================== Hardware is fully functional, as far as we could tell. There may be further improvements in quality, but in its current form it works smoothly for laboratory testing. Software is what makes it "beta": * Only 1st channel is supported in the software at this moment. * Not all LMS6002D controls are properly integrated into the software. * Safe/production bitstreams switching is not working in the FPGA yet. * Result of the TCXO frequency synchronization from GPS is not stored to EEPROM. * I/Q imbalance and DC leakage calibration are not automatic. We accept patches to fix these and other issues. You participation will make the stable release closer. ;) The software is based on UHD from Etttus Research, so if you're familiar with it, it'll be easy for you to get into. UmTRXv2 package contents ======================== * UmTRXv2, flashed and ready to use. * Power supply, 12V/30W - http://www.phihong.com/assets/pdf/PSAC30U.pdf Note, that it comes without a 220V power cord. Make sure to prepare one before you receive the UmTRX to be able to power it on immediately. ;) * Converter cable from a Molex power connector to a standard round DC connector. * U.FL-to-SMA-F pigtail cables * Two small antennas - one for Tx and one for Rx. * An Open-Source Telecom T-shirt! (see the picture attached) Feedback ======= Do not hesitate to contact us if you have any questions, suggestion or comment. We love your feedback! -- Regards, Alexander Chemeris. CEO, Fairwaves LLC / ??? ??????? http://fairwaves.ru From alexander.chemeris at gmail.com Sat Dec 15 15:17:24 2012 From: alexander.chemeris at gmail.com (Alexander Chemeris) Date: Sat, 15 Dec 2012 19:17:24 +0400 Subject: UmTRX beta aka Limited Edition sales start! In-Reply-To: References: Message-ID: Now with the t-shirt picture. On Sat, Dec 15, 2012 at 6:37 PM, Alexander Chemeris wrote: > Dear all, > > We want to make a Christmas gift for the community and it's my > pleasure to announce the start of sales of UmTRXv2 beta samples aka > Limited Edition. > > What is UmTRX? > ============== > > UmTRX is an SDR transceiver, which we, Fairwaves, developed > specifically for OpenBTS. It's similar to USRPs, but is heavily > modified to be the best hardware for OpenBTS. More details are > available at the project web-site: > https://code.google.com/p/umtrx/ > > > Ordering and Shipping > ===================== > > To claim your UmTRXv2 Limited Edition, please fill in this form: > https://docs.google.com/spreadsheet/viewform?formkey=dGVHNlNDaXVoSHp2eC1EcVFPcXFXLWc6MQ > You will receive a payment link shortly after we receive your answer. > The shipping cost will be estimated when we have everything ready for > shipping, we'll contact you again by then. > > There are only 14 units in this Limited Edition batch, so we allow you > to claim only 1 or 2 units. > > The base price for a UmTRX is $1500 just as we promised. Since we are > relying on your support to fund further development, we encourage you > to donate an additional amount. You donations are critical for us to > produce the best ever hardware for OpenBTS. The 5 highest pledgers > will become the proud owners of UmTRX Serial Numbers 1 through 5 and > will be recognized on the UmTRX project site. > > Shipping will be from Paris, France with FedEx or some other express > carrier. We plan to ship as soon as we receive orders for all 14 > units, so the shipping date is not fixed yet. We'll contact you when > we fix it. > > > What does "beta" mean? > ====================== > > Hardware is fully functional, as far as we could tell. There may be > further improvements in quality, but in its current form it works > smoothly for laboratory testing. > > Software is what makes it "beta": > * Only 1st channel is supported in the software at this moment. > * Not all LMS6002D controls are properly integrated into the software. > * Safe/production bitstreams switching is not working in the FPGA yet. > * Result of the TCXO frequency synchronization from GPS is not stored > to EEPROM. > * I/Q imbalance and DC leakage calibration are not automatic. > > We accept patches to fix these and other issues. You participation > will make the stable release closer. ;) > > The software is based on UHD from Etttus Research, so if you're > familiar with it, it'll be easy for you to get into. > > > UmTRXv2 package contents > ======================== > > * UmTRXv2, flashed and ready to use. > * Power supply, 12V/30W - http://www.phihong.com/assets/pdf/PSAC30U.pdf > Note, that it comes without a 220V power cord. Make sure to prepare > one before you receive the UmTRX to be able to power it on > immediately. ;) > * Converter cable from a Molex power connector to a standard round DC > connector. > * U.FL-to-SMA-F pigtail cables > * Two small antennas - one for Tx and one for Rx. > * An Open-Source Telecom T-shirt! (see the picture attached) > > > Feedback > ======= > > Do not hesitate to contact us if you have any questions, suggestion or > comment. We love your feedback! > > -- > Regards, > Alexander Chemeris. > CEO, Fairwaves LLC / ??? ??????? > http://fairwaves.ru -- Regards, Alexander Chemeris. CEO, Fairwaves LLC / ??? ??????? http://fairwaves.ru -------------- next part -------------- A non-text attachment was scrubbed... Name: Open-source T-shirt final.png Type: image/png Size: 251393 bytes Desc: not available URL: From stephane at shimaore.net Thu Dec 27 13:54:54 2012 From: stephane at shimaore.net (stephane at shimaore.net) Date: Thu, 27 Dec 2012 14:54:54 +0100 Subject: Building firmware Message-ID: <20121227135454.GA21547@shimaore.net> Hi, While I'm waiting for my umtrx to show up, I'm following the "let's play newbie" route and trying to use the instructions on https://code.google.com/p/umtrx/wiki/BuildingUHD I got stuck for a short while on step #2. It would probably be useful to add at the beginning of step 2 something like: git clone git://github.com/chemeris/UHD-Fairwaves.git Also I see the FPGA instructions use ISE 14.2, should I download that version rather than the more recent one (14.4) on Xilinx' site? Finally, is the Ethernet flashing going to work off-the-box on the beta umtrx or is it better I buy a JTAG cable? In that later case is the Digilent HS-1 the recommended cable? S. From plddesigner at gmail.com Thu Dec 27 16:38:36 2012 From: plddesigner at gmail.com (Andrew Karpenkov) Date: Thu, 27 Dec 2012 20:38:36 +0400 Subject: Building firmware In-Reply-To: <20121227135454.GA21547@shimaore.net> References: <20121227135454.GA21547@shimaore.net> Message-ID: Hi, Stephane, You can use any ISE version above 14.1. UmTRX would shipted to you already flashed. But If you'll spoil UmTRX with a wrong image, you can unbrick it with JTAG cable only. For this purposes we use Xilinx Platform Cable USB and Digilent HS-1. ? ?????????, ?????? ????????? 2012/12/27 > Hi, > > While I'm waiting for my umtrx to show up, I'm following the "let's play > newbie" route and trying to use the instructions on > https://code.google.com/p/umtrx/wiki/BuildingUHD > > I got stuck for a short while on step #2. It would probably be useful > to add at the beginning of step 2 something like: > > git clone git://github.com/chemeris/UHD-Fairwaves.git > > > Also I see the FPGA instructions use ISE 14.2, should I download that > version rather than the more recent one (14.4) on Xilinx' site? > > > Finally, is the Ethernet flashing going to work off-the-box on the beta > umtrx or is it better I buy a JTAG cable? In that later case is the > Digilent HS-1 the recommended cable? > S. > > -------------- next part -------------- An HTML attachment was scrubbed... URL: From stephane at shimaore.net Thu Dec 27 19:15:01 2012 From: stephane at shimaore.net (stephane at shimaore.net) Date: Thu, 27 Dec 2012 20:15:01 +0100 Subject: Building firmware In-Reply-To: References: <20121227135454.GA21547@shimaore.net> Message-ID: <20121227191501.GA30051@shimaore.net> > For this purposes we use Xilinx Platform Cable USB and Digilent HS-1. Given the price difference I'll go with the Digilent cable. (Not a biggy: what is the role of the "USB Debug" port?) Another question wrt OpenBTS configuration, is it sufficient to do: ./configure --with-uhd or does umtrx need other options (--with-resamp, --with-extref)? Also I assume the transceiver code is the Transceiver52M version and I should just do cd apps ln -s ../Transceiver52M/transceiver . S. From plddesigner at gmail.com Thu Dec 27 20:01:50 2012 From: plddesigner at gmail.com (Andrew Karpenkov) Date: Fri, 28 Dec 2012 00:01:50 +0400 Subject: Building firmware In-Reply-To: <20121227191501.GA30051@shimaore.net> References: <20121227135454.GA21547@shimaore.net> <20121227191501.GA30051@shimaore.net> Message-ID: At boot time, in USB debug port you can see such information as lms chip version, speed of Ethernet phy, MAC and IP address of UmTRX board (and much more, it's defined in ZPU bootloader firmware). Another question wrt OpenBTS configuration, is it sufficient to do: > ./configure --with-uhd > or does umtrx need other options (--with-resamp, --with-extref)? OpenBTS with UmTRX board required only --with-uhd option. Also I assume the transceiver code is the Transceiver52M version and I > should just do > cd apps > ln -s ../Transceiver52M/transceiver . Yes, You're right. Regards, Andrew Karpenkov 2012/12/27 > (Not a biggy: what is the role of the "USB Debug" port?) -------------- next part -------------- An HTML attachment was scrubbed... URL: