./jack.sh

Unifi recently (and finally) brought Unifi Talk to UK shores, having an ISDN2 PBX that is almost 2 decades old it seemed like the perfect opportunity to upgrade.

One small snag, Unifi isn’t currently supporting number porting to their Talk service for the UK.

Our current provided offers a SIP Trunk service supported by Gamma – so Unifi Talk is just SIP how hard can it be…

Talk is essentially Freeswitch behind a UI and Unifi goodness, so its a reasonably well documented and understood system, and can support practically any SIP provider you’d care to imagine.

Talk configures two scopes internal and external.

Internal listens on port 5060, and External can listen on a registered port or when Static Signaling is enabled port 6767

Gamma has a couple of interesting requirements:

• Uses Static IP as “Auth”
• Uses Fixed Port 5060 signaling.

This presents the first problem, we can’t simply port forward 5060 from the internet to 5060 internally as Talk will treat that SIP traffic as internal and the ACL will block it.

We instead need to move the traffic with a firewall rule, taking external traffic on 5060 and forward it to 6767 (the static signaling port) with that completed we also need to allow Internet In traffic for that local forward.

Configuration

Step 1) Setup Port Forwarding Rules from Gamma Provided IP ranges

Step 2) Configure FW Rules

Step 3) Enable Static Signalling

Gamma doesn’t support registration, or allow inbound ports to be easily change we therefore need a fixed port to forward. Handily Static Signaling exists.

Step 4) Configure Unifi Talk SIP Provider

Step 5) Test

That should be all that is required, if you have one way audio confirm port forwarding and Internet Local rules are properly configured.

When Garry Shandling passed away in 2016, he was widely remembered as a top stand-up comic and the star of two of the most innovative sitcoms in TV history. But to those who knew him, the “real” Garry Shandling was a far more complex person. Now, Judd Apatow has created a remarkable portrait of this iconic comedian in the four-and-a-half-hour documentary The Zen Diaries of Garry Shandling.

Sky Atlantic: The Zen Diaries Of Garry Shandling

A Shepard tone, named after Roger Shepard, is a sound consisting of a superposition of sine waves separated by octaves. When played with the bass pitch of the tone moving upward or downward, it is referred to as the Shepard scale. This creates the auditory illusion of a tone that continually ascends or descends in pitch, yet which ultimately seems to get no higher or lower.

https://en.wikipedia.org/wiki/Shepard_tone

When scientists first discovered the megamouth shark in 1976 off the coast of Hawaii, it struck them as so bizarre that, to classify it, they created an entirely new genus and family.

Today, little is still known about the shark save for the fact that it has a large gaping mouth, which is indeed, very mega.

http://news.nationalgeographic.com/2017/07/rare-megamouth-shark-sighting-video-spd/

Benjamin Zander has two infectious passions: classical music, and helping us all realize our untapped love for it — and by extension, our untapped love for all new possibilities, new experiences, new connections.

In 2009 he was flying 700,000 miles per year. Last year he hit 17 million flown, which would mean 7 million in 5 years or 1.4 million per year — twice his earlier pace. That would be 3835 miles per day which would require flying literally a third of the hours in each year.

Source: Next Week Tom Stuker Will Fly His 18 Millionth Mile on United Airlines

This is still one of my favourite mad engineering stories on the web. How to fix a 230kV oil filled electricity cable with Liquid Nitrogen.

It turns out they have a problem with an underground wire. Not just any wire but a 230 KV, many-hundred-amp, 10 mile long coax cable. It shorted out. (Lotta watts!) It feeds (fed) power from the Scattergood Steam Plant in El Segundo to a distribution center near Bundy and S.M. Blvd.

To complicate matters the cable consists of a copper center conductor living inside a 16 inch diameter pipe filled with a pressurized oil dielectric. Hundreds of thousands of gallons live in the entire length of pipe. Finding the fault was hard enough. But having found it they still have a serious problem. They can’t afford to drain the whole pipeline – the old oil (contaminated by temporary storage) would have to be disposed of and replaced with new (pure) stuff which they claim takes months to order (in that volume). The cost of oil replacement would be gigantic given that it is special stuff. They also claimed the down time is costing the costing LA $13,000 per hour. How to fix it and fast?

That’s where the LN-2 comes in. An elegant solution if you ask me. They dig holes on both sides (20-30 feet each way) of the fault, wrap the pipe with giant (asbestos-looking) blankets filled with all kind of tubes and wires, feed LN-2 through the tubes, and *freeze* the oil. Viola! Programmable plugs! The faulty section is drained, sliced, the bad stuff removed, replaced, welded back together, topped off, and the plugs are thawed. I was amazed.

Source: engineering pornography