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Dutch & Dutch 8C Smart Volume Control with Philips Hue Dial

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Dutch & Dutch 8C active speakers have a very comprehensive web interface, also encapsulated into a phone App, that allows configuration of all the supported modes, inputs, DSP filters etc. I wanted to be able to incorporate the speakers into my existing home automation setup, that's based on Home Assistant. So I wrote a custom component for HA that allows for control of all the basic features of the 8C: Volume, Input and Preset selection, track navigation.  Github link One thing that was still missing in my setup was a decent volume control solution, as depending on an app to control the device volume is annoying, and using multiple remotes to control volume of different devices is confusing for non-technical users. I recently learnt about the Philips Hue Tap Dial switch, for which support has been added to Home Assistant. Since I already had a Zigbee network set up, this seemed like an ideal solution.  It provides four buttons and a rotary dial that can be hooked up to ac...
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Time Electronics 9814 IEEE-488 Interface testing

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I mentioned in an earlier post about this instrument that I might try to get IEEE-488 working with it. I'd naively assumed that one could simply search on eBay for "USB to IEEE-488 interface" and pick something up that would have an open source Linux driver for about £10.  I was slightly surprised to find that the new price for such an item was actually over £1000, which I suppose just demonstrates that IEEE-488 was never used outside of labs, and as such, why leave money on the table by making it cheap ? Anyway, it turned out that there's a very nice  Arduino project  that just needs a cable to be wired up, so I thought I'd have a go at that since I had a Mega in the cupboard. AliExpress obliged with a cheap cable that I could butcher, and I set to work with a set of pins and some crimping pliers After a bit of crimping, sorting out the wiring diagram from the AR488 manual, and full checking for connectivity, I had this mess The AR488 software needs some minor co...
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Ubiquiti Edgerouter IPv6 (Zen Internet UK) plus Tayga NAT64 configuration

Nearly 23 years after starting a new job managing IPv6 development at Cisco Systems, I've finally ended up with an ISP here in the UK that actually supports IPv6. So I thought I'd better turn it on. Zen Fibre still uses PPPoE, and they give you a static /64 via SLAAC and a static /48 that's allocated via DHCPv6-PD.  Although the prefixes are static, it appears that you have to use PD to make a prefix request, in order for routing for the whole /48 block to be enabled in your direction.   The configuration I ended up with is as follows. I disable use of the ISP's DNS server as I've got my own local server with ad-blocking. The firewall setup isn't shown, but blocks all incoming traffic, allows ICMPv6, established sessions and DHCPv6.  A caveat about using the Edgerouter's PD implementation is that the "service slaac" clause auto-generates a basic radvd configuration for that interface. However, this then gets overwritten if you explicitly configure ...
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Time Electronics 9814 Programmable Voltage Calibrator

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I left school having just turned 17 after my 'A' levels in 1980, needing to fill a year before going to University, and ended up working at Time Electronics in Tonbridge.   The company made electronic calibration lab instruments, and I worked there for a year before University, and then in most vacations subsequently until I started my first post-graduation job at DEC in 1984. More reminiscences about this in a future post perhaps. The biggest project I was involved with was a new range of programmable instrumentation, with remote operation via IEEE-488/GPIB and local front panel controls. This range included voltage and current sources, a programmable resistance, multi-way switch, and screwdriver *(1).  Later on, a multi-function calibrator was produced, combining several functions in one unit. Since I retired from actual paid employment a few years ago, I've been slowly collecting working versions of things I worked on during my career.  For example, using simh, I ...
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Ubiquiti Edgerouter ER-X Flash issues (free space, hangs, firmware upgrades)

  The ER-X is a very cheap 5 port router, with a lot of enterprise-level software features. It's almost too cheap, because it doesn't really have enough Flash memory, and certainly with earlier samples, the Flash itself was rather unreliable. For a start, there isn't enough Flash space to store three images, so when you want to upgrade the firmware, you always need to delete any old backup version that's still installed to make enough free space ("delete system image" CLI command). The firmware upgrade process ("add system image") itself can be rather hit&miss on devices that suffer from unreliable Flash, requiring multiple attempts to succeed. The symptom I found is an apparent hang at the "Copying Image" stage, with a crash and reboot after a few minutes. There are many reports on the Internet of ER-X having random hangs with various software versions, in particular there's a symptom where IP forwarding seems to work normally, but...
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DECnet-VAX Phase V P.S.I. configuration in open_simh

The addition of HDLC framing support to the DUP11/DPV11 devices in open_simh extends the number of networking products can be used under VMS in the simulator. The most obvious product to demonstrate is VAX P.S.I., which provides X.25 connectivity.  This example uses P.S.I. in its simplest possible mode, with two systems connected back to back, one configured to act as a DCE (X.25 is asymmetric).  P.S.I. is shipped as part of DECnet-Plus, so if you chose not to install it originally, re-run "PRODUCT INSTALL" for DECnet-Plus, and answer yes to the question about installing P.S.I. The rest of your configuration will remain unchanged. A valid license for "P.S.I." is needed to get started.   If you're feeling confident, you can just run @sys$manager:psi$configure and go through the configurator, to produce your own startup scripts. To avoid needing to run the configurator, and just use the example scripts below, do the following while logged in as SYSTEM: $ set def ...
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DECnet-VAX Phase V WAN connectivity in open-simh using an HDLC datalink

  DNA Phase V introduced HDLC as a supported WAN datalink for use with DECnet.  HDLC framing offers efficiency gains in terms of bits transmitted compared to DDCMP, especially with short packets.  The default frame size was larger, and a 32 bit FCS was optionally supported for improved error detection. Current versions of open-simh, as of this blog post, support HDLC framing on the DUP11 and DPV11 devices. Read the previous post about installing and configuring DECnet-plus to get started.  Then, rather than configuring a DDCMP datalink, you simply configure an HDLC datalink instead. Unfortunately, the VMS DUP11/DPV11 driver has more bugs that affect HDLC operation when used with open-simh, so some additional patches are needed. The following is a superset of the previous patches required for DPV11 DDCMP and those required for HDLC, so will give a driver that works for both: $ patch sys$loadable_images:sedriver.exe /absolute repl/inst 3f25 'MOVB (R7),B^07(R0)' exi...
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