Posts by NITS 128 publicly visible posts • joined 29 Nov 2020
Back in the day I was using my laptop to troubleshoot the network connection to a cash register in a department store. I placed my laptop on the counter and went to the switch closet. Upon my return, the machine had blue-screened. I had absent-mindedly set it atop the magnetic thingy that detaches the antitheft tags, and it had degaussed my drive while it was running.
I once worked for an American company that provided totalisator systems to racetracks, for the convenience of punters who wished to invest in equine performance futures. Expense advances on the road were never a problem; just ask the company's system operator for a check, and take it to the money room next door!
CCTV video cables are 75-ohm RG-59/U, and use 75-ohm BNC connectors. They will mate with 50-ohm BNC connectors. Not perfectly; ISTR that the center pin diameter is a bit different.
The failure that results is less obvious than when you shove a USB B plug into a 10baseT ("RJ45" - NOT!) socket. Or insert a VGA plug by feel, upside-down. The pin layout is symmetrical, and there is enough 'give' in the D-shaped male shell that it will re-mold itself to match the female that you're inserting.
I was called out to fix the IP phone in a gas station kiosk. The attendant said that it goes out mostly on rainy days in the spring and summer. The station is located around the corner and a block away from its parent grocery store. I took a walk outside and saw that there was a microwave antenna on the gas station canopy, and another on a mast on the roof of the main store. When installed, it would have had a clear line of sight over the roof of the 1-story strip shopping center that occupies the corner lot. Problem was that a hotel had been built, diagonally in from the strip mall. When the saplings that originally adorned the hotel's parking lot and sidewalks had begun to grow into proper trees, the leafy green microwave absorbers began to block the path . . . especially on rainy days in the spring and summer.
I wasn't able to mitigate their circumstance that day, but listening to the user's description of the symptoms pointed me toward the diagnosis. I haven't been back to the site since, so I don't know how they remedied it -- a buried fiber optic cable, a separate ISP connection to the gas station, or some other fix such as a passive repeater that would have been line-of-sight to both ends of the microwave link.
Just now, another possible remedy comes to mind -- replace the trees with bonsai??
Some months back we did a tech refresh. We were required to affix to the monitor a P-Touch label with the machine name as displayed by W11. Problem was, the machine name was displayed in a typeface with ambiguous glyphs, as mentioned above. Not only little L / capital I / the digit One, but also Zero and capital O were ambiguous*. We ended up copy-and-pasting the name as displayed in the "About" screen, into a Notepad instance -- the serifs in Notepad's default character set resolved the ambiguity -- so we could generate the labels correctly. I've been using the Times Roman typeface in my labeler ever since.
*Not to mention 6, 8. 9. and 0 in some typefaces, aggravated by poor lighting and inkspread.
Back in the day I used Bell Centennial on my MythTV system. Intended for telephone directories printed in small sizes on low-quality paper, Bell Centennial has extra-large ink traps so the inside corners of the glyphs looked crisp even if there was inkspread. It looks crisp on CRT monitors also.
They make WAPs that use an external antenna. Seen 'em used in big-box stores with the antenna inside the cooler and the WAP outside. Also. with the antenna outside the building and the WAP inside, to provide coverage in the parking lot, truck dock, outside lawn-and-garden, etc. One thing I've never figured out is why in bl**dy heck they made these so that if you install them with the writing right-side-up, the LAN connectors face up, and collect any condensation from cold roof trusses, water from roof leakage, etc.... I have seen several destroyed when moisture had made the PoE sizzle inside the connector and fry the contacts. I would remount the replacement WAP "sideways" if possible, and/or improvise a tent out of a piece of cardboard and a plastic bag, to reduce the risk of liquid contamination recurrence. It wouldn't do to mount it upside down, because gravity + vibration would encourage the WAP to slide off its mounting bracket. I've always wondered if this design was the result of someone not paying attention to how their product would be used, or was a subtle form of planned obsolescence (a.k.a. a triumph of marketing over engineering).
On the subject of RF and metal boxes... I've been to several locations of a chain restaurant (think "neighborhood bar and grill" or something like that) where the intrusion alarm had been updated, and all the contacts and sensors were replaced with wireless ones. The installer had concealed the transmitters for the door contacts inside metal Handyboxes* with metal covers. Not a perfect Faraday cage, but it did confine the Hertzian waves to the extent that the control panel reported "loss of supervision". My solution was to install plastic junction-box covers from the DIY store.
I later learned that this installer had done the same thing at over 20 sites, and was not pleased to have to revisit them all to rework them.
* a Handybox is a North American single-gang electrical junction box. It is intended to be surface-mounted, not concealed in a wall. It is drawn, so that it has rounded corners, versus being made of folded-and-welded flat sheets of metal and having sharp corners.
I suspect that, rather than being the cause, the frozen pipe was an effect of passing through the cold area under the floor.
I've experienced the opposite: In my college years, my parents fixed me up a bedroom in the basement. The basement bathroom floor (tile over concrete) was curiously warm underfoot. Turns out that the domestic hot water feed to that bathroom passed through that area of the slab. After we figured it out, we reran the feed through the ceiling. I never thought to ask whether they noticed a change in the gas or water bills.
Differential drivers and receivers are useful, bot without optical isolation the magic smoke escapes if the common-mode voltage exceeds the chips' limit -- typically, 25 volts if I recall correctly. Grounding and bonding are great, but all bets are off when the building gets hit by lightning, or even a near miss.
They used to sell (and probably still do) conductive rubber grounding straps that you could attach to your car's (metal bumper, in those days) to discarge static that built up whilst driving.
Toll booth lanes, back when we handed cash to a collector, had a flexible metal rod that would rub the cars' underbodies to prevent shocking the attendant.
In a computer room with racks of minicomputers (and a couple of 900 line/min printers), the operator kept a spray bottle with Downy fabric softener to spritz the carpet and help keep the static dissipated.
I've worked in a place with well-grounded equipment in a room with epoxy-painted floors. My sneakers (trainers, for the East Pondians) would get me static-charged as I walked across the floor. I learned to carry my keys in my hand to act as a lightning rod as I approached the equipment.
I've noticed that my denim jeans will rub up a static charge as I slide off the car seat. Best to discharge away from the gasoline filler neck!
I am surprised that wrist straps were not mandated at the Alpine observatory cited by the first commenter.
I think that you meant LATA (Local Access and Transport Area). Not the same as a Numbering Plan Area (from whence "Area Code"). See <https://en.wikipedia.org/wiki/Local_Access_And_Transport_Area>.
FTA: "LATA boundaries tend to be drawn around markets, and not necessarily along existing state or area code borders. Some LATAs cross over state boundaries, such as those for the New York metropolitan area and Greenwich, Connecticut; Chicago, Illinois; Portland, Oregon; and areas between Maryland, Virginia, and West Virginia. Area codes and LATAs do not necessarily share boundaries; many LATAs exist in multiple area codes, and many area codes exist in multiple LATAs. "
As a grocery saw a checkstand conveyor belt that wouldn't shut off when the afternoon sun flooded in the front window onto the photoeye receiver. Higher-spec photoeyes have used a modulated beam so they can filter out signal from DC sources such as the sun, or mains-frequency hum from ambient lighting. I wonder how well that works now that the lighting uses switching power supplies.
My current car has the digital controls and displays. It drives me nuts. It over- or under-heats to regulate the cabin temperature to make a small sensor at a location unknown to me, very happy. The "automatic" setting runs the fan at high speed until it catches up; I've learned not to use it. I am forever poking at the up/down rocker (an additional driver distraction) to work around it in an attempt get it to blow air to make me, the driver, comfortable.
What I want is a big knob with an arrow that's blue at one end and red at the other, that I can reach without looking for it, that will tweak the temperature of the air blowing on my face and hands to a comfortable level. Like all the other cars I've previously owned.
Reminds me of that old cartoon with the 6 different versions of a tree and a tire swing.
I once worked for a subsidiary of a Fortune 500 company. We were finding ourselves on credit hold from time to time. Supplier's terms might be 2% 10, net 30. The bean counters would take 60 days, and take the discount besides. We engineers leveled with the salesmen, told them that that was the way of the beancounters, there wasn't any way to change it, and to factor it into their pricing. No more credit holds after that.
At another employer, we found ourselves on credit hold after manglement in their indefinite wisdom acquired another firm, which had markers out all over the place. Failure of "due diligence".
An outfit that I have done contract work for, was acquired. Their standard terms were 60 days, but you could join their Rapid Pay program to get paid in 10 days, with a 2% discount. After the acquisition, they changed it from 10 calendar days to 10 business days, and changed the terms from 2% to "whatever the XXX mortgage interest rate index is". But the mortgage rate index is per-annum, and they were applying it to a 46-day period. It worked out to something like 161% APR when I did the math. Usurious! I'll wait the 60 days, thanks.
I've run into that scenario several times. Most recently, it was a 2.5 hour drive to the site, an extra 1mm shove on a patch cord end until it clicked, then the link light came on. I ended up replacing the patch cable anyway, because the clip had taken a set due to having been depressed to the extreme and not allowed to spring back into the latched position. Then, another 2.5 hour drive back to the office.
A pet peeve of mine is when a device's power brick has an IEC22 plug, there's no shelf or other convenient support, so the weight of the power brick was left dangling from the mains cord, resulting in disconnection of the power cord. Velcro's your friend!
I had one the other day where a switch was down in a hotel. The IDF had an electronic keycard door lock that had malfunctioned. There was no physical key, just the electronic lock. We ended up using burglars' tools to get in: a stiff wire fished under the door, bent to be able to snag the lever knob on the inside and let us in. The switch was down because there was no power to either of its redundant power supplies. Both of the power cords were sourced from the same UPS, which was not working. I unplugged the UPS from the wall outlet to verify that the outlet was live (it was), and plugged it back in. It started on its own, and the switch came up. Moreover, there were 4 switches, and 4 UPSes, in that IDF. They were all connected identically, such that the UPS was a single point of failure for its switch. I offered to replug the switches to diversify the power sourcing, but the client said to leave it as it was. I would not be surprised to get another callout to this site.
It was, if I recall correctly, a Christmas Eve several decades ago. I was heading out from Maryland to a destination in South Florida to support the opening of the winter meet of a hippodrome. I was booked on the last flight of the evening. I had with me 9 boxes of plastic admission passes -- like credit cards, but different -- for the meet, which I had picked up at the manufacturer and was transporting as checked luggage. Uncharacteristic of me, I arrived at the airport hours early. The plan was that my SO would drop me and my stuff at the curb, go and park the Microbus while I checked in with the airline, and we would enjoy a relaxed casual meal at one of the airport's restaurants, since I would be away for the actual holiday.
When I got to the check-in counter, the monitor was showing that my intended flight was canceled. The agent confirmed this, "but we can get you on the earlier flight, if you hurry!" This was several decades ago, so no TSA. Also no mobile phone, so no way to contact my SO. They threw my boxes and luggage on the baggage belt, didn't take the time to process the excess-baggage fees. I said "Do me a favor. In a few minutes, a young lady will come here looking to meet me. Would you please explain to her what happened?" With that, I sprinted toward the gate.
The relationship survived.
Decades ago, in at least some parts of North America, the telcos assigned coin-operated public telephones numbers in the 9xxx block. They did not allow collect calls to be made to a coin phone. The 9xxx phone number was a red flag to the operator. When I made a collect call from the college dorm's hall phone to my parents, there would be an additional delay as the originating Bell of Pennsylvania operator would have to verify with Chesapeake and Potomac that my parents' landline, 647-9046, was NOT a coin box before completing the collect call. I found that if I included the phrase "and no, it's not a coin box, it's my parents' home phone" in my initial request to set up the call, they would take my word for it and skip the time-consuming verification step.
Easton, Pennsylvania still had an electromechanical telephone exchange in those days; I believe that it was the step-by-step variety using Strowger switches. There was a wonderful (to my ears) cacaphony of clicks, clacks, and buzzes audible outside the telephone exchange building. I regret not having thought to ask if our electrical engineering department could arrange a tour of it.
Some years ago our tween son was doing home school. Part of it was online. More-that-a-bit obsessed with all things LEGO, he kept visiting sites like lego.com when supposedly doing school. A few entries added to the hosts file put an end to that.
I've since confessed to having done it.
... is what I call it. One of those metal sticks, about a meter long, with an S bend at the far end, and a wooden handle, that shop staff use to hang and retrieve merch from a tall hook on a display wall. Useful for fetching wires, and also for steering fiberglass cable-running sticks through that J-hook that you just can't reach.
Also useful: a 10-ft length of steel sash chain, for fishing cable down a wall cavity. Hole above the ceiling line for cable entry, another at the equipment mounting point. Attach cable end to the top, dangle the chain down the wall cavity, and use a magnet to retrieve it.
But wait, there's more! A traffic cone, to manage cable at the corner where the cable path turns. Walk it out to length on the floor, coil it up using the sound techs' over-and-under technique, lay the coil over the cone. It feeds off without kinking. Repeat as required at the next corner(s) of the cable path.
I've installed alarm systems. One way to test a glass-break detector is to whack its mounting surface with a screwdriver handle, and immediately shake a ring full of keys near its microphone. It takes the combination of low- and high-frequency (maybe ultrasonic?) sounds to trigger it.
Was told to bring a 10ft stepladder to a gig the other day. I could just barely reach the switch by standing on its tippy-top; a 12-footer would have been much safer (and OSHA-compliant). I survived my venture into "la zona de muerta". The rack was firmly attached to the wall, so I had a decent handhold at least.
CP/M systems, 8 inch floppies written at a particular field site would not read at the office. The (full-height) drives had AC motors. In the field we had 10KVA inverters (double-bay cabinet, batteries big enough to run a forklift). The inverters had a free-running oscillator that ran close enough to 60 Hz for most purposes, but the disk spindle rotation speed was sufficiently off that the data couldn't be recovered in a system powered by the mains. Our solution at the office was to power the B drive off the mains,and power the A drive off an audio oscillator, which drove a 100-watt PA amplifier via a step-up transformer. Adjusted the gain to get 120V, tweaked the oscillator frequency until the floppy would read. Then PIP B:=A:*.* for the win.
Later systems had half-height drives with DC motors and their own timebase, so the issue went away.
Place I worked at had field sites that used 900 line/minute Dataproducts drum printers. 3-copy greenbar carbon paper. They'd run them without the covers. The systems printed for a few seconds every minute. Most of the reports went right into 55-gallon plastic Rubbermaid trash cans parked behind the printers, but could be retrieved if required. There were a few pages that were used, printed as an event went off. They were pulled off and handed to the customer. The system printed longer reports at end-of-day. The covers might be closed then. Many of the operators seemed partially deaf from exposure to the noise from the open printers.
Each site had a decollator (remember those?) to separate the pages and the carbons.
My employer had been quite loyal to Dataproducts, but when they switched from towel ribbons to cartridge ribbons, the latter proved unreliable. So when the Centronics salesman showed up one day, and he had (formerly CDC) band printers with towel ribbons in his catalog, we jumped on that.
Our next-generation systems used laser printers.
I once worked at a place that had one of those to accommodate a blind programmer. The Braille printer appeared to be based on a daisywheel printer. It had a single stylus and embossed the dots into fanfold tractor-feed card stock. It was loud, even with its accoustical enclosure's cover closed.
Just a couple of weeks ago a chap I know closed a months-old ticket concerning a user's repeated corruption of the config files for a particular mission-critical application. The vendor's support folks hadn't been able to figure it out. In the log files it became apparent that a proper Windows shutdown was not occurring. Not only was the user failing to exit the application, he was in the habit of pressing-and-holding the power button to shut down his machine at the end of the day. It was faster that way, and nobody had ever told him not to do it that way, so why not?
Some of my least-favorite calls were to remediate issues with a weighing-and-labeling scale having gone offline in the deli department of a big-box store. The usual cause was a corroded network jack under the deli case, Sometimes it was green corrosion on the jack and/or plug. Sometimes it was corroded wires on the punchdown side of the jack.
Access to the underneath of the deli case requires lying on the floor, removing the toe-kick plate, and reaching in to the area under the case where the grey slime ends up when they wash the floor. They pretend to seal the junction with the floor with silicone caulk, but it never adheres. It's always yucky down there.
Not inherently bad. Just certain kinds. The 75 ohm ones used in CCTV, mostly legacy now, I think. The modern compression type are pretty good. But I run into the older hex-crimp ones that were applied with the wrong tooling. They go bad (or were bad, just not detected). And there's a special corner in a very hot place reserved for anyone who thought that making, or using, the ones that don't crimp at all, they just have a female screw thread to capture the shield. I find those causing problems a lot. I can imagine the marketing speil: Easy to apply! Saves time! No tooling! No crimping! Just twist on and go! I think I remember seeing them in Radio Shack blister packs.
Honorable mention: the DVR makers who jam the BNCs so close together that you (or at least I) can't get fingers between them to do up, or undo, the retention rings. I find them unlatched, and the plug having worked its way out, sometimes.
Used to get dispatches for $DEVICE OFFLINE in various branches of a big-box store. Wireless access points weren't too bad to deal with, though some of their IDFs were a she-dog to reach. Often, the failed unit was one of the WAPs with external antennas outside the building, with RF cables through a wall penetration to the WAP located in the (theoretically) warm-and-dry interior of the building. The WAP would be mounted on or under the structural steel. I would find the network jack corroded or burned up from water intrusion collecting in it, whether from condensation or from an actual roof leak, and getting sizzled by the PoE power.
For the life of me, though, I can't fathom why Cisco thought it a good idea to put the jacks on the TOP edge of the WAP, when mounted with the logo right-side-up, so that the jack would collect water that ran down the cable. (It's not just Cisco, though; their competition seem to do the same thing. A subtle form of planned obsolescence, perhaps?)
I would try to remount the WAP sideways, or make a plastic-bag tent to prevent recurrence.
The absolute worst calls were for failed connections to scales in the deli. The LAN cables run under the customer-facing display/cooler cases. There was at least one jack-and-plug located under the case, perhaps more if the scale had been moved from its original location or the cable had been serviced previously. Access to under the case requires lying on the floor and removing a toe kick plate, which often showed evidence of attempts to silicone-caulk it to the floor. The caulk was not usually intact, and in any event was not intact after I removed the access plate. There was usually a grey slime under the case, washed there from cleaning the tile floor. Not a great place to be working. Wet environment, corrosion, etc., etc., the fault was often due to corrosion at the interface between the cat5 cable and the punchdown terminals on the jack. The repair itself was not so bad, just punching on a new jack and/or plug and replacing a patch cord. But the grey slime -- yuck!
What does NOT work is using a 4P4C (4 position, 4 conductor) handset cord modular connector instead of a 6P2C RJ11 plug.
1. The handset connector has pointy contacts designed to penetrate a tinsel or stranded wire, different from the contacts for solid wire that penetrate the insulation and straddle the solid conductor, capturing it in a fork. They may appear to work for a while, but they stub against a solid wire and do not make a gas-tight connection. Time and environmental factors, or mechanical manipulation, will cause them to fail open.
2. The 4P handset connector, while it may insert and latch into an RJ11 socket, does not have enough support and can rotate about the cable axis, causing an open circuit.
I've seen this (and replaced the connectors to repair it) in several branches of a department-store chain, where they converted from POTS trunking to VOIP, installing ATAs (Analog(ue) Telephone Adapters) to provide dialtone to their legacy phone system. The ATAs were built to a budget, of course, and their RJ11 sockets had only the 2 required center contacts. So the handset plugs were not as well supported as they would have been if used in a 6P4C or 6P6C socket. Found this condition several times on callouts for "Line 3 is dead" and such.
I know, they now make (and I have used) mod ends with contacts intended to work with either solid or stranded wire. But these were not that type.
IT work can be a lot like janitorial work, cleaning up other people's messes.
When doing field support (a.k.a."monkey with a screwdriver") I am always careful to refer to the Wide-Area Network port and the Local-Area Network port in so many words when talking with the customer's support desk, to avoid the ambiguity of the similar-sounding acronyms.
A department store, several branches of which I have had occasion to visit, does not provide dedicated aircon to their server rooms. Rather, they see fit to install an outlet from the building's main HVAC system. Maybe, in theory, it worked OK when first installed; I'll give them the benefit of the doubt. But over time, Stuff Happens -- more equipment added to the MDF room, duct gets disconnected, system becomes unbalanced for some other reason. More than once, I've walked into one of their rooms and found it rip-off-all-your-clothes hot. I suggest to manglement that they *really* should get their Facilities folks to address the situation, and they say "Oh, it's always like that!"
