Visited: Vivid Sydney (10th Anniversary: 25 May – 16 Jun 18)

Every year, the festival of light, music and ideas comes to Sydney, transforming the harbour and surrounding areas into a vibrant bustling work-of-art. This year, Vivid Sydney celebrates its 10th anniversary and as with previous years, I just had to partake and take some photos.

Visiting Vivid

Rather unfortunately, I’ve been more busy this year than in previous years, so I didn’t have many chances to visit. The first day I was able to visit was rather late in the calendar (8th June), but worst of all, it didn’t stop raining at all. Grey skies aren’t exactly appealing in photos too, nevermind the sogginess.

The upside to this was a lack of passengers on the train to Circular Quay (a classic, un-airconditioned S-set) and only the “mildest” of crowd management strategies were in force, making for easier and shorter walks. Luckily, I had a rain jacket, so I was still warm and dry, but I can’t say the same about my non-weatherproof Nikon D3400.

The photos taken with the phone camera show drops of water falling off the lens and camera. It was that much, but I still persevered. Luckily, no camera equipment was harmed in the process, although it did impact on my enjoyment of the event somewhat.

What was more challenging was that I still haven’t upgraded from my Nikon D3400 with a dodgey central focus spot. Taking photos in low light using the other focus spots is not easy. Another challenge was doing it with a dodgey tripod (one of the leg clips is loose) and a lens with a dodgey autofocus mechanism. I have always wanted to upgrade but being stuffed around by eBay sellers that never fulfill their orders doesn’t help.

After getting the equipment somewhat wetter than it should have gotten, I decided to suspend photography just to go look at the exhibits. In the first night, I was able to see the whole Rocks, Circular Quay, Royal Botanic Gardens and Chatswood precincts. It seems that due to development, the Rocks area seems to have less exhibits than in the past, but the Royal Botanic Gardens have grown their area to compensate somewhat. This year sees no Martin Place, but Luna Park is now a part of it too. Darling Harbour, Kings Cross and Barangaroo remain features although the number of exhibits there are rather limited by comparison.

The difference from the past years? It seems that the exhibition is quite focused on tourist dollars, with a large number of food trucks where the simplest of foods start at a floor price of AU$12. Talk about a price gouge! I suppose one can still enjoy the lights and have something to eat at a regular fast food chain, although the queues do get crazy (understandably).

Not content with visiting just once, I decided to visit a second time on 12th June – this time, to much more pleasant weather. This time I was able to take some more photos in the Royal Botanic Gardens, re-visiting exhibits I saw last time, while taking a walk down to Barangaroo and Darling Harbour. I didn’t find the latter two precincts too interesting, so I left the camera in the bag and just enjoyed it with my eyes – that being said, the laser effects at Darling Harbour seemed a little audacious with some laser scanning “into” the audience and reflecting off the water into eyes nearly-directly. While it’s quite visually stunning, it’s also potentially risky … my quick phone photo caught a beam on a near direct hit. Depending on the laser power, it’s not unknown to have image sensors ruined by them, so I didn’t chance my DSLR to it.

What follows is a “mixture” of photos from the DSLR from the two visits.

Photos

Good ol’ Circular Quay, complete with more beams of light traversing the skies than ever before. Would it have been this bright at night without the advent of LED technology? Probably not.

A view from ground level – the lasers on top of the coat-hanger add that special touch to an otherwise “normal” LED-lined bridge. On the side, there is Come Fly With Me exhibit. Heading towards the Opera House, the crowd control measures are apparent, and the exhibits are relatively “thinly” spread at the edges allowing for better movement.

Opposite, there is Visible Dynamics, which sort of feels like stacked spinning tops. It has a sort of “clicky” sound … with colour-changing LEDs.

On long exposure, the LEDs trace out different shapes. Further along the harbour, there is Fragmented, which draws inspiration from stained-glass windows.

The main draw is always the Opera House projections. This year’s projection is named Metamathemagical and was quite an interesting mix of patterns, shapes and objects. It even seemed abstract at times.

With all of the crowds and restrictions in front of the Opera House, the best place to view the projections was across the harbour. But if you’re in front of the Opera House, it’s also a good place to admire the harbour.

While I’m not a big fan of obvious sponsor exhibits, I think Samsung deserves credit for outdoing expectations. Their exhibition, The Night. Reimagined. saw queues that I haven’t seen in a long time.

They took a prime position just in front of the house, near the entrance to the Royal Botanic Gardens, but in return, they delivered an interesting round exhibit which featured a lot of LED lit frames. All of these frames were co-ordinated to music in a rather mesmerising result even if you didn’t bother to queue to get inside.

On a wet day, the reflection from the water on the ground really makes it seem futuristic, almost like a space ship or an RTG.

Of course, there were marketing messages throughout, but some of these deserved some pause for thought. Like this one …

… which said “Capture the moment within the moment”. An interesting phrase, as I was doing that in some way – the moment of those inside the “shell” from my moment, outside the shell behind the barriers.

But inside or out, people can’t help but be captivated by such an interesting installation. Good work Samsung!

The Royal Botanic Gardens doesn’t disappoint either. While some installations, like this lit-up tree are rather simple, others are not.

The Nautilus Forest was quite impressive. LED trees which were co-ordinated and changed from time to time create a very interesting atmosphere.

Light Houses shared a similar “intelligence”, this time it seems that each unit is like a display that could show different patterns.

Oasis was rather captivating as well, especially when the fog rolls in the right way across the LEDs. Unfortunately, the wind wasn’t co-operating at the time, but the colours and reflection from the water were wonderful.

One of my favourite exhibits was How Many Light Bulbs…? While it’s a bit of a thought-provoking meta-style twist to the classical light-bulb joke, it’s also quite a technical feat which a tinkerer like me appreciates.

The display itself is giant. It puts LED display-boards to shame, although it does only display a fixed message. With the help of a little HDR on the less-rainy day, although affected by “bloom” in the lens …

… we get a better sense of the scale. While the 2570 light bulbs in the exhibition wasn’t enough to change me, it was a rather interesting exhibit nonetheless just for the sheer scale. If we think of the original joke … it seems some of the light bulbs need changing!

Yep. There’s a few out. When I returned the second time, there were more of them out, so I decided to get a good shot just to see how many had failed.

A total of 79 failures means about a 3% failure. Whether this is due to weather affecting the connection, or low quality bulbs, I’m not sure. But lets assume that they’re running on the Vivid 6pm to 11:30pm schedule (5.5 hours per day), then they have only run about 101 hours (18 days + 2 hours). An MTBF calculation for the population would be approximately 101 x 2570 = 259,570 total hours / 79 failures = 3286 hours which is quite woeful.

This is because, up close, they are made of 6 LEDs each. From my back-of-the-envelope, each bulb is probably about 0.72W, so the display consumes 1850.4W – quite a bit of energy indeed.

Government House also saw a little make-over with Photonic State doing some light-mapping projections. Just in front of that, Aqueous was getting a number of people involved in an interactive way.

Conclusion

By the time this article is published, Vivid Sydney would be in its last few hours for this year. It’s been another good year, even if the weather wasn’t so great. There were a lot of exhibits I didn’t end up photographing – I was more busy trying to experience as many of the exhibits in my limited time rather than take photos, but the ones I did take photos of, I was quite thoroughly impressed with.

While the event seems to continue to evolve, I’ll definitely be coming back next year to see what the artists get up to. After all, it’s free, and it’s an event which draws out crowds of photographers and families alike.

Rather unfortunately, I didn’t have time to visit the Transport Heritage Expo this year, so there won’t be a posting about that. I also just remembered that I went on a pretty decent holiday last year – but I haven’t posted much about it either … maybe I should get around to that before I forget all about it.

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Project: Record a K56flex Dial-Up Modem Connection

Inspired by my previous post made merely an hour ago, I set to work seeing if I could acquire a recording of a K56flex dial-up modem connection before it is too late. After all, both X2 and K56flex are more “at risk” of extinction (if not already) compared to the ITU standards-ratified V.90/V.92. Sadly, while I had three Australian points-of-presence to dial into, only one persists today.

The K56flex Camp

If you haven’t read the previous posting about X2, it’s probably a good idea as it is quite relevant to this post as well. The K56flex camp was basically the only competition to X2, which launched almost simultaneously in February 1997. The K56flex camp was made of Rockwell (holding a large majority share of consumer chipsets) as well as Lucent and Motorola (who dropped out of the modem business soon afterwards). The standard itself served to cut USR’s hopes of becoming a de-facto standard for 56k modems and resulted in USR’s collaboration in coming together with the joint ITU V.90 standard, although not without some annoyances from the parties as to USR’s majority control.

Adoption of 56k modems were somewhat hampered by incompatible modulations – it seems that Rockwell chipsets dominated the low end of the market and by extension, K56flex was more widely adopted at the consumer end. However, when it came to ISPs in the USA, it seems that X2 had a firm lead, judging by “The Need For Speed And The Copper Wire” by Lisa A. Phifer in June 1997.

Very few user devices supported both standards –

However, in “Coordination vs. differentiation in a standards war: 56K modems“, a working paper by Angelique Augereau et.al in 2004 has the table below:

While only covering the early days, this particular table seems to suggest that while X2 enjoyed some early popularity, K56flex did take the upper hand only a few months later. It also acknowledges the general lack of industry data availability.

Of the protocols, K56flex was rather unique in having only speeds divisible by 2kbps, which include 32, 34, 36, 38, 40, 42, 44, 48, 50, 52, 54, 56kbit/s. Upstream remains V.34 and the system by which it works is the same as X2 in exploiting the digital nature of the server modems. If the speed limiting commands of certain K56flex modems are to be believed, a provision for 58 and 60kbit/s is also made.

The K56flex Handshake

In order to capture a K56flex handshake, I needed to identify a K56flex capable modem. For the most common Rockwell/Conexant chipsets, the AT+MS command is used to select modulations. Querying it for its settings with AT+MS=? should provide a list of supported values. Only modems which accept 56 or K56 claim to support K56flex. Many upgraded modems with smaller flash chips will only support 12 which is V.90, or may fail to negotiate flex despite accepting 56.

The particular modem I chose was my Netcomm Roadster II 56k Ultra SVD which supports both modes in its firmware. By forcing the unit to use modulation 56, I can ensure a K56flex connection is established.

ati3
V2.210-K56_2M_DLS

OK
ati4
NetComm RoadsterII 56 V.90 F02_V1.56 (C) NetComm Ltd. 1999

OK
ati6
RCV56DPF L8570A Rev 47.32/47.32
OK

at+ms=?
(0,1,2,3,9,10,11,12,56,64,69),(0,1),(300-56000),(300-56000),(0,1),(0,1),(300-33600)

OK
at+ms?
56,1,34000,56000,1,0,33600

I tried calling my last remaining point of presence that can be reached on my Australian VSP and possibly the last actually operating. Using my Grandstream HT702 was fruitless, as a V.34 connection was always negotiated. Only when I moved back to my venerable Linksys PAP2T was I greeted with a glorious result – a pretty speedy K56flex connection.

Make no mistake – this is no V.34 connection. The sound of a K56flex connection is different. As with my convention, the digital modem is on the left channel, the analog calling modem is on the right. The standard ranging signals are used and scrambled data is sent right after, but the frequency and “scratchiness” of it is different. It sounds as if someone’s cutting in and out a few different high-pass filters. There’s no obvious digital impairment learning sequence as with V.90.

at&v1
TERMINATION REASON.......... LOCAL REQUEST
LAST TX rate................ 28800 BPS
HIGHEST TX rate............. 28800 BPS
LAST RX rate................ 48000 BPS
HIGHEST RX rate............. 48000 BPS
PROTOCOL.................... LAPM
COMPRESSION................. V42Bis
Line QUALITY................ 025
Rx LEVEL.................... 013
Highest Rx State............ B3
Highest TX State............ 67
EQM Sum..................... 00BB
RBS Pattern................. 00
Rate Drop................... 00
Digital Loss................ None
Local Rtrn Count............ 00
Remote Rtrn Count........... 00
Flex 9481834246E0

OK
at&v2
BEGINaa14ab14ac14ad14ba25bb25bc25bd25ca77cb67cc153da4ea0eb0fa110fb110fc110ga10gb4ha25hb21hc25hd0he9hf187hg0hh0hi0hj23hk21hl0hm255hn255ho255hp255hq255hr255hs255ia26ib26ic26ja0jb0jc0jd0je0ka0kb1kc0kd0ke0kf0kg0kh1ki38kj0kk2kl81km33kn255la103lb179lc103ld104ma0mb0mc6na2nb0oa0ob0oc0od18oe34of0og235pa1pb0qa0qb1qc255ra43rb148rc129rd131re66rf70rg224sa255sb255sc255END

OK
at#ud
DIAG <2A4D3263 0=10>
DIAG <2A4D3263 1=07>
DIAG <2A4D3263 2=00>
DIAG <2A4D3263 3=00>
DIAG <2A4D3263 10=0D>
DIAG <2A4D3263 11=0A>
DIAG <2A4D3263 12=1A>
DIAG <2A4D3263 20=81>
DIAG <2A4D3263 21=81>
DIAG <2A4D3263 22=0C80>
DIAG <2A4D3263 23=1F40>
DIAG <2A4D3263 24=0725>
DIAG <2A4D3263 25=00>
DIAG <2A4D3263 26=7080>
DIAG <2A4D3263 27=BB80>
DIAG <2A4D3263 30=00>
DIAG <2A4D3263 31=00>
DIAG <2A4D3263 32=00>
DIAG <2A4D3263 33=00>
DIAG <2A4D3263 34=7080>
DIAG <2A4D3263 35=BB80>
DIAG <2A4D3263 40=01>
DIAG <2A4D3263 41=80>
DIAG <2A4D3263 42=00>
DIAG <2A4D3263 43=00>
DIAG <2A4D3263 44=01>
DIAG <2A4D3263 50=02>
DIAG <2A4D3263 51=02>
DIAG <2A4D3263 52=00000005>
DIAG <2A4D3263 53=0000003F>
DIAG <2A4D3263 54=0000>
DIAG <2A4D3263 55=0000>
DIAG <2A4D3263 56=00000003>
DIAG <2A4D3263 57=00000004>
DIAG <2A4D3263 58=0000>
DIAG <2A4D3263 59=0000>
DIAG <2A4D3263 60=51>

OK

While the diagnostics available on the modem aren’t good enough to say clearly that it is a K56flex connection, it almost certainly is. For one, the connect rate is divisible by 2kbps. Secondly, there was no DIL sequence in the call – the modem defaults to V.90 and produces the two-tone crescendo as per my V.90 collection of sounds. Finally, the speed is above 33.6kbit/s, therefore cannot be V.34.

What is more surprising is that it was able to get a 48000/28800bps connection reliably on a VoIP connection terminated to my local VSP via LTE mobile broadband going through a triple-NAT. It’s a case of all the stars aligning to make it happen.

Conclusion

These pre-standards 56k modem technologies are a little more difficult to catch “in the wild” primarily because they were not that popular and because many of the modems were upgraded to later V.90 standard firmware which often removed support for older pre-standard modulation due to lack of flash memory storage. I remember having a pair of disks I could use to switch a Rockwell ACF modem between its K56flex and V.90 firmwares. Rather luckily, I was able to find a more “premium” modem with simultaneous dual-standard support and a point-of-presence that still supported the protocol. Count that as curiosity satisfied!

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Project: Record a US Robotics “X2” Dial-Up Modem Connection

Throughout the long history of dial-up modems, higher connection speeds were always desired, but limitations in signal processing techniques and the phone lines themselves meant that achievable rates were always going to be limited. At various stages in time, the “absolute” limit of what could be put through a phone line have increased thanks to more complex modulations, error correction protocols, improved echo cancelling for full duplex operation and finally, by exploiting the digitally connected nature of later telephone networks.

While the ITU had done the market a big favour by standardising modem modulations, the need for speed meant that a number of manufacturers were willing to push the boundaries to develop their own modulations ahead of the ITU standard. Such non-standard modulations include Hayes Express96 (9.6kbit/s), USR HST (9.6-24kbit/s), Telebit (18.4kbit/s), V.32terbo (19.2kbit/s), V.FC (28.8kbit/s), K56flex and X2 (56kbit/s) to name a few.

Owing to the nature of the (now) practically all-digital carrier network, even in a perfect world, a phone call is only represented by 64kbit/s of data each way, thus representing the absolute limit of the dial-up technology. Real-life impacts of signal noise, amplitude and frequency response non-linearities, robbed-bit signalling, digital pads and codec mismatch mean that even getting 56kbit/s is rare. Where the network is analog at both ends, or the call is converted to analog and back again to digital, the realistic limit is 33.6kbit/s.

US Robotics X2 Technology

At the time when V.34 was just around offering 28.8kbit/s at its peak, US Robotics (USR, later 3com) sought to deliver twice as much bandwidth, calling their technology X2 (sometimes written as x2). USR saw success in the past with their proprietary HST modems and as a leading name in modems at the time holding 40% of the retail modem market, were well placed to disrupt the market.

The X2 technology worked (according to the whitepaper from USR) by exploiting the fact that the ISP’s modem banks are often connected to the switching network on a pure digital connection. If the connection remains digital through to the line-card that is serving the customer with no other analog-to-digital connections in the path, the signal to noise ratio on the downstream (from the ISP) link could be high enough to support greater rates than the V.34 standard allowed. Part of this boils down to a reduction in quantisation noise resulting in more voltage levels being able to be reconstructed. This advantage is not available in the upstream, as the customer modem and telephone line are analog, and thus the upstream remains V.34.

According to the USR Sportster Voice 56K modem manual, X2 technology is capable of customer download rates of 33333, 37333, 41333, 42666, 44000, 45333, 46666, 48000, 49333, 50666, 52000, 53333, 54666, 56000, 57333bps. However, rates above 53333bps are not permitted in the USA by the FCC due to power output limitations. Using X2, the customer upload rate can be 14400, 16800, 19200, 21600, 24000, 26400, 28800, 31200bps, although all V.34+ link rates could possibly be available.

USR had a healthy head start on the technology, especially as existing modems that they sold were DSP based and firmware upgradeable to X2. They started an ISP Xtreme Advantage Program to give ISPs some free exposure if they deployed X2 technology in their points of presence. By early 1997, they were shipping X2 modems to retailers and Stephen Hawking and Steve Wozniak were both chosen to be the face of X2 on a TV advertising campaign. The last capture of the news from the USR X2 site shows that even as late as February 1998, ISPs were considering deploying X2 technology.

Rather unfortunately, X2 was not the only “quasi-standard” in town. K56flex, championed by Rockwell (who had a commanding 80% share of the chipset market), Lucent and Motorola also made it to market in early 1997.

Both X2 and K56flex had some rocky beginnings and 56kbit/s modem adoption was (to some extent) dampened by the incompatibility of these standards. Specifically with regards to X2, it seems that there were gripes with the ISP-side modem equipment, as well as problems from users getting X2 connections which angered early adopters.

Rather luckily, change was on the horizon with the ITU V.90 standard being developed between March 1998 and February 1999. Rumours about this must have been around, as even as early as mid-1997, USR was promising customers free upgrades to a future ITU-standard to try and maintain market share. However, it seems that soon after the introduction of V.90, USR pulled support for X2 altogether. Some modems couldn’t get upgraded to V.90 in the end due to a lack of flash memory, and 3com settled a class action lawsuit over their 56k “claims” without admitting fault. Rather interestingly, this exchange from a 3Com engineer seems to point to the introduction of the DIL sequence in V.90 as being a big reliability improvement over X2.

Unfortunately, history will recall X2 as a market failure, if it even recalls it at all. It’s unclear how far X2 got outside of the USA – USR’s market dominance of modems was probably not as strong outside of the USA and as a result, I don’t recall there being an X2 capable ISP in Australia. The X2 system may not have been optimised for operation over A-law companding phone networks outside of the USA, which natively uses mu-law companding.

Nonetheless, it has always been a wish of mine to hear an X2 handshake “in the flesh” and (if possible) make it happen with my own equipment in real-time.

Getting an X2 Handshake

This whole blog post was inspired by an e-mail I received from a reader. The e-mail gave me some information which led to a modem bank in the USA which still supported X2. The reader did attempt a number of connections which were able to at least partially-negotiate X2 before falling back to V.34. As a result, I set my sights on the case.

Configuration Profile...
Product type           Australia External
Product ID:            04562501
Options                V32bis,V.80,V.34+,x2, V.90
Fax Options            Class 1/Class 2.0
Line Options           Caller ID
Voice Options          Speakerphone, TAD
Clock Freq             92.0Mhz
EPROM                  256k
RAM                    32k

FLASH date             11/12/98
FLASH rev              14.2.15

DSP date               5/7/97
DSP rev                10.3.79

I grabbed my USR Message Modem Pro PCB (as the case had long disintegrated into dust) and hooked it into my Grandstream HT702 to give it a whirl with my local VSP, placing a paid international call. I was able to achieve a V.34 connection but not stably. The audio was captured through Wireshark sniffing of a bridged interface where my ATA was connected, which showed amplitudes which were all over the place. I suspect the modem itself may be a little old and screwy.

Eliminating variables, I moved back to my venerable Linksys PAP2T ATA and instead terminated my calls through a US-based VSP. This method surprisingly bore more fruit, as an attempt at an X2 connection was made. Tweaking the input gain to obscene levels finally resulted in an X2 connection being successfully made.

An X2 connection sounds like this. The left channel is the digital modem at the ISP, the right channel is my modem. The call starts off similarly to most V.34 calls, but mid-way through the first ranging signal, the calling modem sends scrambled data upward. From there, it’s only a few blips in-between scrambled segments and a connection is made.

U.S. Robotics 56K Professional Message  Link Diagnostics...

Chars sent                    3      Chars Received                0
Chars lost                    0
Octets sent                   0      Octets Received               0
Blocks sent                   0      Blocks Received               0
Blocks resent                 0

Retrains Requested            0      Retrains Granted              0
Line Reversals                0      Blers                         0
Link Timeouts                 0      Link Naks                     0

Data Compression       NONE
Equalization           Long
Fallback               Enabled
Protocol               NONE
Speed                  44000/4800
x2 Peak Speed          42666
Last Call              00:00:04

Disconnect Reason is Escape code

U.S. Robotics 56K Professional Message  Link Diagnostics...

Modulation                  x2/V.34
Carrier Freq     (Hz)       None/1920
Symbol Rate                 8000/3200
Trellis Code                None/64S-4D
Nonlinear Encoding          None/ON
Precoding                   None/ON
Shaping                     ON/ON
Preemphasis      (-dB)      0/0
Recv/Xmit Level  (-dBm)     18/16
Near Echo Loss   (dB)       8
Far Echo Loss    (dB)       0
Carrier Offset   (Hz)       NONE
Round Trip Delay (msec)     559
Timing Offset    (ppm)      7655
SNR              (dB)       41.3
Speed Shifts Up/Down        0/0
Status :                    0000,0001,0000,0000,0000,0000,0000,0000

Connection statistics from ati6 and ati11 are above. I disconnected the call pretty soon after connection with +++ followed by ath0 simply because I knew the call isn’t likely to hang on for long, the server at the other end never sends anything and I didn’t need any more seconds of white-scrambled-noise in the recording. The connection did complete at 42666bps, although the speed line says 44000/4800bps, so a speed change may have been on the cards. The three sent characters are the escape code.

In order to make an X2 connection, the command ats32=66 is needed to disable V.90, as most X2 capable servers have also V.90 capabilities and modems which are both V.90 and X2 capable will prefer V.90 mode.

A call without this S-register setting completes in V.90 as below.

The sound of the V.90 connection is the standard USR “bong” type which represents the DIL. Notice the V.34-like standard ranging signals complete fully, rather than being interrupted.

U.S. Robotics 56K Professional Message  Link Diagnostics...

Chars sent                    3      Chars Received                0
Chars lost                    0
Octets sent                   0      Octets Received               0
Blocks sent                   0      Blocks Received               0
Blocks resent                 0

Retrains Requested            0      Retrains Granted              0
Line Reversals                0      Blers                         0
Link Timeouts                 0      Link Naks                     0

Data Compression       NONE
Equalization           Long
Fallback               Enabled
Protocol               NONE
Speed                  44000/16800
V.90 Peak Speed        44000
Last Call              00:00:03

Disconnect Reason is Escape code

U.S. Robotics 56K Professional Message  Link Diagnostics...

Modulation                  V.90
Carrier Freq     (Hz)       None/1920
Symbol Rate                 8000/3200
Trellis Code                None/64S-4D
Nonlinear Encoding          None/ON
Precoding                   None/ON
Shaping                     ON/ON
Preemphasis      (-dB)      0/4
Recv/Xmit Level  (-dBm)     20/16
Near Echo Loss   (dB)       8
Far Echo Loss    (dB)       0
Carrier Offset   (Hz)       NONE
Round Trip Delay (msec)     680
Timing Offset    (ppm)      7629
SNR              (dB)       41.4
Speed Shifts Up/Down        0/0
Status :                    uu,5,12N,12.2,-0,1N,0,38.9,25.0

The connection was successful at 44000/16800bps. The last status line shows that the codec is properly matched – uu meaning mu-law on both sides (important as Australia is a-law by default). The higher rate of connection may reflect pure luck or more refinement on the V.90 standard as a result of being the combined efforts of a number of different 56k efforts. The upstream rate is still rather low, but trialling V.34 connections to the same server, it was possible to achieve either 31200/31200bps or 33600/26400bps connections, so it doesn’t seem to be one particularly “bad” direction but more-so that maybe the high energy of the digital downstream may be echoing into the upstream enough to reduce the SNR significantly.

Noting that all of these connections were achieved over a VoIP link carried over RTP/UDP on the public internet where delivery is not assured, across from Australia to the USA makes this especially significant as I have no landline anymore.

Conclusion

US Robotics was a leader in the modem industry and tried to bring 56k technology to consumers in their own way through their ill-fated proprietary X2 technology. While they were not the only ones to try, eventually, the ITU’s V.90 standard rendered both X2 and K56flex obsolete. Having only encountered one recording of an X2 connection online in the past on a website that no longer exists, it has been a longstanding desire of mine to actually witness a live X2 connection and record it. I can definitely say I have achieved that, which is amazing considering how long ago X2 was discontinued and the relative lack of land-line and dial-up users at present. To be able to do this in 2018 is very surprising.

Might the same be possible for K56flex as well? I don’t know … as almost everything I’ve tried is V.90 capable and won’t do K56flex due to being firmware upgraded. Likewise, I don’t have much choice in modem banks either … Maybe it’s time to crack out an older Rockwell or LTWinmodem, Windows 98SE, an old driver and make some more calls?

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