ProjectMF 2.0 with NPSTN
11:53PM Jul 29, 2020
Hello everyone and welcome back. Thank you so much for being part of the hope 2020 conference and helping to make this virtual version such a success, we really could not do this without you. So for our next talk, we'll be covering project in F to Dotto with NPT estienne, brought to you by Dylan Cruz, a 17 year old phone freak from sunny Florida who has been interested in telephones for a very long time. And they've been around for much longer. He's particularly interested in the US public until public telephone network of the 1970s and 1980s. So after we get through with Dylan's presentation we'll be doing a live QA session with him. So while we're doing the presentation, please submit your questions to matrix chat, we'll be curating them, and then feeding Dylan so that he can answer them with you. And with that I think we're almost ready to go for the presentation.
villain. So, my name is Dylan. I'm a phone freak. I'm 17, right over here in Casselberry Florida, and today I'm going to be doing a talk on NPS 10. I was supposed to mainly focus everything on project mf 2.0, but unfortunately my friend Michael he recently caught the virus and he he fell ill and we were unable to finish the main source code for Project 2.0. So, I was going to kind of shift directions a bit and talk a little bit a little bit about NPS tn, and how project mf 2.0 will hopefully soon incorporate on top of NPS tn. So right here in my on my screen here I have this is a user control panel for NPS tn. So members they have an off key for for this for this webpage here. But first, I'm going to describe what NPS tn actually is so NPS tn is a peer to peer void network and allows collectors and phone freaks and enthusiasts, to actually connect their switching equipment and their all their telephones, to each other in a seamless manner, and we support a wide range of signaling protocols that were widely used in the Bell System and a lot of other countries like Russia and stuff still use them like mainly NF signaling and SF signaling. One thing we're actually working on now is we're working on an identifier tone detection system. So step by steps which is. They know when to send their mF digits over. So first, let's see here me over here. Here is the member list for NPS tn it's publicly accessible list of all the numbers on NPS tn with their descriptions. As you can see, the wide range of numbers are by Navin. He's, he's great he has a lot of stuff here. But here I wanted to demonstrate a step switch that we have on NPS tn. So here, let's see, I think.
Yeah, here we go.
So here we have this was just put on NPS tn, I want to say a few weeks ago, let's see 869 office code. So as you can see here we have, step by step dial tone so this should be a Dessau into that switch, so I have my micro sip here. Now I mainly use a Linux actually actually run Ubuntu. 16.04 on my laptop, but I'm still at work. So I have this in my workstation here. So let me go over here. Let's tell nine one will give us an outside
case for MTS tn. This is a simulated step by step dial terms so let's call this number one.
Here we have a step by step.
So let's style. 8311
was to it's actually, it's not what it was supposed to do.
This is actually a wrong number. See when it does,
ringing. You can also hear an awful tone in the background if you listen, I don't know if that'll make it over the stream but there's actually an awful tone bleeding on top of green there. That's quite neat. And we also have. Here's a seven eight announcement machine. It's electromechanical it has a drum and it has this little rotating head and that goes around your Let's
see here. A.
This is a direct circuits are busy now.
See, I didn't let us dial it directly. I guess we'll just dial on top of the dial.
Oh, okay. Hang up on.
Let's try this one more time. Let's actually try this.
Okay, actually I already tried
to. What was your one.
And I think it's gonna work. In
this recording and error.
Check the number and try you're gone again,
that's coming from a Western Electric seven eight announcement system. Let's see what else we have on here. Um, let's see, was always fun is dialing into switch verification messages. What is which verification messages is usually you will dial it in this is still on the PSTN today, mainly in New York City is you'll dial like the area code the prefix it's usually on 901, sometimes it can be on something else, but it will read the location of the switch the switching equipment type and all the office codes it serves. So on NPS tn, we do have something similar as you can see right here. This one is by Sean 7919901, let's try that.
Welcome to the NPS tn au s y 01 exchange in Sydney, Australia, this exchange serves code, 791, the exchange operator can be reached on 7910000. This is a recording. 79125. Welcome to the PSTN.
And as I'm making these calls, if I go into the UCP and I clicked on. Let's go, white pages. 64612 and seven which is what the soft phone is over here.
It will actually give us what it looks like it's getting cut off there a tiny bit. It'll actually
what NPS team does is we have a mock billing system, it'll actually.
It'll actually come up with what the charges would be for the calls in the 19th. It's based on 1970s rates. So as you can see here here some calls I just made to Matthews, Virginia, those 869 numbers I was dialing into that step switch. And here you can see how long the call was, and the amount. And here's a North Sydney, Australia, and the number I dialed. And let's see, it also has a date and everything here. And then on the side we have our message units for one month, the calls outside the local area. The telegrams which I'll get into a bit about that in a second. Other charges, we have like little United States fee little directory advertising fee their service and equipment for dollars now. Now this is based on 1960s and 70s rates with inflation that's actually quite a while not quite a bit, but if you know it. It'd be almost about what you'd pay for a phone bill today. Not really close but kind of in that ballpark, it's not just $4. Let's see here. Um, so if I go back over here. I want to dial something that actually seems so we can see all the charges here.
well actually all those 869 numbers. Some of those should have saved, the one Australia did not though, actually.
Let's see here.
So one of Levine's numbers actually. So what Levine's done, is he put together on his Asterix system, he wrote 10s of thousands of lines of code simulating different various different crossbar and step by step systems with immense detail, like real attention to detail, and he got all the sounds from Evan doorbell and also from recordings of a few telephone museums and actually he took, I believe, like a notice he took like a summer at Stanford and they actually had a step by step PBX still in operation as of 2018. And as far as I know it's still in service today at kz su studios, and he has a few of those recordings, up here, I believe. Let's see here. Other than Evan doorbell has all of his recordings here on ESPN on the, the 747 office code. I believe he there's like 1000 recordings here for oven doorbell but directly dial.
Let's find out. Let's find a good number on the Dean's system, let's see.
To get one.
The will on the 444 office code is numbers that we've dialed from the freak net prif cough, and we've compiled it into little recordings, so all mostly everything here in you'll find in the 444 office code is mainly stuff that's usually still viable on the PSTN today. Let's see like there's this one number here this is welcome to gt Express dial tone. Let's see if this one still works actually
263. I don't know if it will or not.
Hang up. Then pick up and dial for a three.
So, yeah, as you can see that still on most of everything, 444 is still in service. And let's see,
finding out good numbers, see here.
I'm sorry this is taking so long. Let's see. Oh yes all joy bubble stuff revert of pulsing sample. Try that one actually.
As you can see that was actually reverted pulsing, which a lot of older electromechanical telephones, which is actually used to signal each other. It was a very weird signaling protocol it basically did pulses, in this weird. I don't actually understand how the protocol works but I know it sounds really cool. And I know if you dial into the museum of communications I believe they have some stuff that uses reverted pulsing. Let's find something that goes on for a bit longer than that. Maybe will dial one of his verification messages, which I believe
is a play on
crossbar 123. Thank you very much.
So some of you might
be crossbar one serving codes, 231,
and PSTN and a Oh 1231912835449650 and sunplus Hubbard. Thank you very much.
We'll do it again. So, what he has there is for each one of these little office coats he has on his asterik system. They all each have their individual verification announcement, and after that times out. It rings, his master verification announcement that's for that list every one of the office codes on his system. So everything he just listed there are the office codes He currently has on NPS tm plus and minus a few. One of the cool ones he has is a 355 here.
fears everything as in 355. Now, each, each thousand blocks and 355 is supposed to be a recreation of like a big PBX system, see like right here it says 3553 xX xX through eight xX xX our PBX party lines each 100 group is a separate conference, each sub exchange has its own personality. So a lot of stuff on the venous system you can actually talk over there's a lot of intercept messages and even on busy signals reorder ringing, you can actually talk on top of it. And one thing we're currently working on now is with some Asterix patches we developed, is to use cough bridges without answer supervision. Without the call. I mean, so what we can do with that is, we can have busy signals and stuff, not supervise, but at the same time, we can have it so you can still talk over it just like on the old network. So let's style one of the VMs simulated a PBX party lines. Let's see here.
See, let's try three xx
crop or something.
Grab another stone over here. Should.
So that was an example of talking on top or through a PBX party line on the venous system. So, that really kind of allows you to grasp the feel of the old network because on the old network you were never really alone. You know there was always something in the background you know and you could always hear someone else on you know another, another trunk and a lot of really cool things like that and that's what we try to recreate on NPS can, because a lot of people like me, for example, you know, we're really interested in this stuff but we never actually had, we never actually got to have that experience we never actually got to to experience that on the phone network for ourselves. So we kind of felt left out in a sense, and we wanted to not only preserve the history but also experience it for ourselves and the only way we can experience it ourselves is, if we can recreate it. So for that reason, it is really cool that that Evan doorbell. Like he was able to preserve that much of the old network, I mean he has just countless hours of various different recordings and guesses raw tapes where he has, like, like ringing tones that are like uninterrupted that are like several minutes long, and it's really useful for us because we can go in and we can actually sample that. And obviously, you can't really come close to recreating the old network there's, there's so much at play you know every little thing you know it all adds up. And it's really difficult and we find that it's really difficult to simulate a lot of the equipment on PSTN. So for that reason we're, we're trying to find a lot of members who actually have the switching equipment, so we can route calls over it, to kind of give in PSTN a more organic nature to it, that's that's one of the things we're trying to incorporate. So that's why we have like there's this several different steps switches and crossbar switches on the network. And with Project mf 2.0 where that comes into play is there is a sub network on top of NPS tn, we call it a step nets. And there's also an SRT the network service and route tandem network. So what we aim to do with that is connect all these steps which is in crossbar switches together and run the project mf 2.0 signaling. On top of that, so project mf 2.0 will convey all those supervision messages on top of that, because a lot of this equipment is just on you know Fx otas, and there's no real easy way of retaining answers to provision. When you're doing that, especially if every single piece of equipment is different. It gets really complicated. So, one method of passing along answer supervision is using an in band signaling protocol. So what we're currently working on is product mf 2.0 to have both ends of that connection, so we can actually play a certain tone, you know if it goes off hook or, or, you know, stuff like that. And the other thing we're doing is we're incorporating that with the NPS tn coin tall ticketing system, where we have currently we have native support for coin phones on NPS tn. I actually did a talk at DEF CON two, a one about this if you guys want to see that. But basically, we can decode coin denomination tones that's the 1700 and 1200 I believe tones that are used by by a lot of pay phones when you deposit a coin, it has a, it plays a coin in plays. It plays a tone in reference to the coin you deposit, and we can actually decode that natively on NPS tn. And one thing you can do is
actually turn this
camera over here. So little webcam. Here's a payphone I actually have over here. I don't know if I can, actually, the audio in last time I did that it didn't really come up very well, but we can actually decode the coin tones and this phone is just connected straight to a regular voice a TA, there is no there's no line card here. Here's actually a payphone line card. This was actually developed by a Howard heart for NPS tn. You can see here. So, technically we don't need to use these, you have to use a card like this if you want to be able to do collect and return. However, We have native support for coin phones without using line cards or any special equipment. The only downfall of doing that is like I said you cannot do collect and you cannot do return. So what you end up having to do is you have to open up the payphone you have to put a zip tie on the coin relay to keep it closed. And by doing that when you deposit a coin it'll fall straight through the chute into the coin volt, which is right here. It's obviously the volt. Psalms, so yeah I mean, it's kind of fun in the fact that you don't have to spend money on expensive equipment in order to use a payphone. Um, but at the same time. Project project mf 2.0 will support the necessary signaling protocols to send collect and return messages to line cards like this in the future, what we're going to have is, you'll have like the line card in between your pay phone and your eta and there'll be a connection between the line card and something like a Raspberry Pi, and that would be a year end. And what we can do is we can use in band signaling on the voice call, and the ataa can actually decode that in real time. And based on the information it can either send the collect and return information over the serial bus to something like this line card here. So that's one thing we're working on. We have some demos of that I have anything I can show you today unfortunately that was what Michael was supposed to help me out with which is unfortunate, but I hope to display something like that, soon on the NPS tn blog shouldn't be more than, like like a week or so from now. But I'm shifting gears I want to also talk about MPs can telegrams. Sorry if I seem a bit like like moving between topics, I didn't really get the time to put together something like it like a PowerPoint or anything so I apologize in advance for that, but over here let's see, we have this tab over here,
where this gets in the way.
Chrome is not. Okay, There we go. So here we have the telegrams tab. So here are all the telegrams I have received. And I can send a telegram by clicking on this button here.
And let's see, that's my phone number, they're probably gonna have to change that. Let's send this to a friend here let's see two telephone number. Let's go to 311121.
Let's put in my number here.
Actually, what am I doing I'm gonna I'm gonna send this to myself actually. That way I can see the call coming in. So phone number would be a 347 5000.
I've never actually tried sending a telegram to myself, so I actually don't know if this will work, it should work though, is 612,
the dummy address.
Hey, we'll have this.
Wait a second.
Actually I don't know what this is,
Actually I don't know what that is, I don't think that was a telegram. Okay, let's see here.
Let's go back over here.
Something came up. See, in time was that I was right here. Well I guess I did receive it. Um, let me see if I can get this to go to someone else. Actually, why don't we just do this by phone here. You can actually send a telegram using a, we should have telegrams 117. Okay.
I'm getting a lot of spam traffic right now.
grams. Can I have the phone number of the recipient, turn this telegram to be sent
form sorry. I'll have no record for any subscriber by that number. Oh, it has to be merged into another number.
now declare your message using stop, in place of full stop. At the end of each sentence.
This is a test telegram for the hope 2020 conference. See, stop.
Word your darker Piper coffee delivered to the recipient. An additional charge of 50 cent supplies.
Please make our payment by cash or cheque or 50 cents payable to Dylan crews 701 sailfish road winter Springs, Florida, three to seven h Hill telegram order number is 30958. Again, that's 30958, be sure to mention this in the memo line. Once your payment is received a printed copy will be immediately dispatched to the recipient. A telephonic and electronic copy will be dispatched immediately, regardless. Okay, give me a minute to send your telegram please.
And then a moment when it's done, sending the telegram CW. I should actually get a telegram on this phone over here.
Here's my Panasonic phone. This is a 347 5000.
So over here on this. This is like backwards on the webcam so it's kind of weird.
Let me actually go to go I'm what successfully sent the recipient should receive it shortly. Okay there we go for using northern union Global Services, I charge for this telegram will appear when you appeal.
So I was gonna say over here on this phone, I have co port number three is 347 5000. I can't really go off look on it just yet because I think the telegram should come in soon, it's on a queue. Let's see. See here. Oh, there's also a TTY relay on here too. Um, let's see what's one thing I can demo. We can dial 118 for a step net trunk, which is it's currently under progress. Your construction I should I should rather say, so this will router call through some simulated step in crossbar switches as well as some actual real electromechanical switches. So, basically after we dial 118 we're going to get a dial tone. From there, I'm going to dial a number on NPS tn, and that should traverse the N PSTN step network.
so that style turned from my step switch across the room I can't really show it to you but let me dial 3211 should ring a station.
I are running generator is actually broken it's supposed to generate a ringback tone. It's supposed to generate a new CDO ring, as I guess what you would call it, but it's only generating the 20 hertz I still have to fix that. And I'm actually still connected to the switch even after it rings it drops back so I should be able to dial it again.
You hear the ring back tone if I
make the volume a bit louder and you can actually hear the truck noise as well as some a little bit of feedback that we're still working on. I don't know if you can really hear that very well. Let's try doing 74 would be a bit loud so I don't want to call that one.
But, there we go, let's
do something else here.
Um, there's also on NPS Can we have a
dial and ring test number as well as a ring back in an X number so I'll demonstrate those briefly.
Tonight five issues should read back to your calling from
And if we dial 959 it should bring us.
guys coming back in. This is kind of losing the field for us since it's not on an actual analog telephone
wish I wish my webcam I wish aquarama webcam was long enough because I don't know if you guys can see this. You might be able to see that over there but I have a little homebrew on switchboard, which actually me and a few of the PSTN operators we actually made a skit on the NPS tn switchboard is called NPS tn operators are committed to service. Um, I don't know if I could get that to play over here and maybe we can do that more towards the end. Let's see here.
Oh, um, I can demonstrate the, the audit cron D STM I built an Asterix arm. So, a friend of mine, Alan from that house telephone. Um, so he has he what he does is he basically gets these auto cron machines and he restores them. So he sent me this was about, like, I want to say maybe back in January he sent me a zip file of all the audio of all the actual individual samples from an audit cron STM machine, one that did time as well as temperature as well as all the advertisements for it, and I was able to successfully recreate that in Asterix with all the samples he sent me here let's see if I can dial into that, it's 32721 to one.
You know what, let me do something real quick, actually, um,
let me see if I can actually get into the Asterix console so I can show you guys.
You can see
the graphic on Asterix
you know it's all synchronized. Here's the Asterix console for the system it's running on. You can see right here. Let me actually make the text a tiny bit bigger for you guys let's see change settings, parents, here we go. Let's change this to, I don't know if 22 is going to be too big. I think that should be a lot better. But as you can see in the background here. That is the dsdm the digital STM is what that's short for. And as you can see here it is actually playing all of the samples in the background. So if I were to dial this, it should be in synchronization with what's coming up here on the Asterix console so it's kind of put this a little bit side by side here.
This is a time of temperature for Elaine.
Oh on your line, dial 611 for repair service on your resitance phones, the time. dial tone calls yourself insane, especially during daily discount periods. The time is 835 835 or 76. It has a temperature,
and then right here it's waiting 2.31300.
Make a list of what you want to talk about you will trade more in less time right here is a
35 or is a variable down it steps up from, I believe it's one to five other than drones, calm down.
To answer the phone rang at least 10 times the rate the time is eight.
There's too much traffic for two or
76. Well what that
does is every time it loops, it changes on your line,
dial 6114 repair service on your residents phones what actually 836 temperature 76. And like many
things on NPS can This is talkable over for a while.
Don't cause yourself and save, especially during daily discount period. The time is eight
business. Make a list of what you want to talk about in less time. The time is 836. I'm talking
over a wide right now.
When we call friends
give them a chance to answer let the
phone ring. So that's the audit cron IDs tm a part of the packet loss on on this computer, I actually did something quite funny so I'm about like 500 feet away from the router that's downstairs and I needed to get telephone service in this room. So what I ended up doing is I didn't feel like running a line all the way from downstairs where on the side of the house where the need is all the way to up here, so I just went in the attic and I actually spliced a connection in between in between that cable and I used two pairs out of it. So I'm actually only on like 100 megabit link on here, but with the all the telephone traffic I'm running through I believe in some way, it degrades my Ethernet service that's also running through there. So I get like very terrible latency on this connection. So that's why I get a lot of packet loss on this, the soft phone for example, but I do actually have a separate connection that goes to, in a TA. That's downstairs and that is running over that other pair which is going to this phone here. This phone doesn't get any relatively any packet loss. Although I can't really couple that easily over here. Let's see
Maybe go back over here. Oh, there's also.
See, this is an
intercept from AV productions. If you want to join the conference line there's a couple of people in here already, it's 332426630 cool.
Here we go. Yeah, let's bring that in here.
Oh, hey. Hello.
Yeah, we had a couple people in there.
Cool. It's a party,
actually do something real quick
just I just remember something real quick.
There's C here, which
I think over here. One thing I wanted to talk about just real quick and then we can pop back into that conference is 311. It's a party line intercept. Here, let me actually see if I can pull this up.
Like I'm actually getting a phone call.
So what this is, is this is a recreation of free one one which has a doorbell did a lot of recordings about where he lived in New York, and what it is, is if you can hear softly in the background there's actually an intercepting message that's playing continuously onto the trunk and it's looped. So when you do all 311 arm, and you join into that conference, you know, you actually have this intercept announcer that's in the background, so other people can dial into it and you can talk on top of the intercept message.
And here I'll join it just real quick.
As you can hear uses some of the. A lot of similar sounds to the one.
If I hang up from
here we actually get all the sounds.
Okay. Um, I just wanted to demonstrate, two more things on NPS tm. One of them is okay, let me actually go over here.
One of them is always
going to demonstrate the operator system.
Sorry about that I should be more prepared about that. Um, let's see here. I wanted to demonstrate the operator system on NPS tn, although all the operators are currently busy, I just checked with them before the conference. A lot of calls right now. I think some
people are are dialing into it, I must have. I actually I shared my number on the talk earlier. Stupid Google Chrome actually auto filled it. Okay, Well, you know what can I do. Okay, let's see here.
I mean I guess that's I guess that's, that's basically it. I wasn't really.
I wasn't really
prepared because just work has been really crazy, I just got hired on as a subcontractor for at&t and it's everything's really just just been quite crazy you know with COVID and everything. I really wanted to put together this really awesome talk and I was starting to do stuff in WordPress but I just I really couldn't focus on it. But this talk was supposed to be a little bit more involved and I was gonna have a little bit more like video backgrounds and stuff and I don't know but i mean you know it is what it is you know, can't really do anything about that but I guess I'm ready to suppose to be a little bit more involved and I was going to have a little bit more like video backgrounds and stuff and I don't know but i mean you know it is what it is, you know, can't really do anything about that somebody's supposed to be a little bit more involved in I was going to have a little bit more like video backgrounds and stuff and I think I'm getting some echo here here. Well, that was a fantastic
talk Dylan really incredible stuff. It's so great to see renewed interest among younger members of our community in our analog roots so kudos to you and all the, the team that was involved in this. And so, maybe you could tell us a little about what got you started in freaking in the first place. Okay,
well first actually I'm, there's a there was a little bit of an echo I actually I think it's gone now. I think this goes way back, I think, the first time I played with the phone I want to say I was five years old, and I was at my cousin's house, and the telephone at my cousin's house it fascinated me because it sounded different than the one we had here at our house, like I would pick up the phone and I would wait for the dial turned to timeout and it's like the intercept message like everything just sounded different to me. And that really kind of piqued my curiosity and that's because I've always been one to mess with electronics, and I've. There's just something about that where you have this whole vast network, and every part of it is a tiny bit different, you know, then, then the other part nothing's exactly the same. And that used to be more so you know a lot of samples. They used to be more so in the 1960s and 1970s when you had all this electromechanical equipment, but it's also still true today, even with all this digital equipment, everything is different, you know everything's programmed by a different switchmen, you know, every company has their own set of standards and policies and I'm gonna have to change my phone number. But, um,
Yeah, I guess what actually
got me into the phone was because of that was because of how different everything sounded to me when I would try to compare things. And I'm just gonna leave the phone off the hook. I would guess
that the the amount of phone calls, you're getting means that your talk has been very well received among the audience.
Yeah, there you go. I'm gonna have to call ma Bell and get my phone number change. I didn't really like my phone number anyways it was like 1131 there's kind of weird sounding So, you know, hopefully I can get a cooler sounding number but,
um, so after I
was five and I had that little kind of interest in phones, it kind of stopped for a while. I never really picked up my interest in phones until I was 12 and I was at a thrift store we were, we were getting afraid exactly why we're at a thrift store, but I was walking there and I saw this 26 this 2500 set right.
And I looked at
it and I was like, that's really interesting. You know, I want to know how that works. You know, so I ended up, begging my mom to get it for me it was like like a 10 or $15 thing or something. And after I brought it home and you know connected it and it worked, like it was really cool. And then I saw you know I kind of want to make this more custom, I kind of want to do something special to this. So that's when I first got my first avoid at a with call centric, and it took me a while to get to the point where I was able to actually create stuff on Asterix. Your first phone.
landline excuse me my first landline telephone I was 12.
And then I was messing with call centric, and then when I want to say when I was about maybe 15 is when I got my Asterix system on it and I just loved all the customizability I had it took my two passions, it took my newfound telephone passion, and my programming passion, and even a little bit of my electronics passion because I get to wire it, and they just combined all those together and it was like this, this awesome thing you know it was, it was like the stars were colliding, it was like. That was perfect and a few years later, I got into peer to peer systems, and well how NPS chain works is we use what's called the CRTC the central route table controller, and it runs on top of PHP it's a publicly accessible API, and you send it get requests. So we have this central route table which is basically just a Maria DB DB database where it has. Everyone's office code, their name zip code email address all their, their switch details like their their hostname their username password all that stuff is stored in that database. So when you send a get request for something like 5551212, it'll look up 5551 in the database and it will return the U ri that Asterix will actually send out, typically using the dial function. And then that's what connects the call. But on top of doing that, we also incorporate logging functions that we use for the billing and a lot of other stuff which all that can be it's all its customizable if you don't want a certain feature, you can just set a flag in the API, like if you don't want billing or you don't want an SRT or whatever you don't want it's fully customizable for your system, which is which is really nice you know. Okay. One of the other things is, is we want to be more decentralized. So currently, what we're working on is what's called the D RTC the distributed route table controller. What that is, is we still have a main central route table right. But what happens is, whenever you make a call on the network, it'll download a local copy to your Asterix system. So then the next time you make a call, it'll First, it will look up to see if there's a record and if there's not a record, then it will request a record. That way, even if our system is offline. You can still make phone calls, just as if it was online, and it, it allows you to make phone calls, more securely and privately, because it never passes through our system. To begin with, because we have local passionate about
it I'm so sorry we have to wrap it up here we're right at the top of the hour, but on behalf of all the hope attendees your fellow presenters and volunteers. Thank you so much for your talk pillen. It was an amazing trip back in time for those of us who remember the public switch telephone network, and a big thanks to all the work you and the others have done to make this experience available for other people to enjoy. So kudos to you, you know it in the matrix chat you continue to interact with the people who may have questions, answer the questions for them and I'm sure there's some people who want to contact with you to figure out how they can be involved in this or learn from you. Thank you for joining us for our next talk at nine o'clock on how Asian makers unite during the covid 19 crisis in Thank you.