Tag Archives: modems

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Ancient Internet

The first company where I worked as a “systems administrator” had no Internet connectivity at all when I started.  By the time I left, I had installed an analog phone line which was shared amongst several users with modems for dial-up service.  The connectivity options in 1995 were limited, and very expensive.  Our company operated on a shoestring budget and could not afford the costly dedicated service offerings from our ISP.

When I moved to a “consulting” company, I finally had the opportunity to work with real dedicated Internet service.  For the customers I worked with, our main options were two:  ISDN and T1 lines.

ISDN stood for Integrated Services Digital Network.  It came in two major flavors, but we exclusively used the lower-end Basic Rate Interface (BRI).  ISDN was a digital phone line, and like its analog counterpart required dialing a phone number.  The BRI had two data channels which were 64 Kbps each, but we usually ran them together for a combined 128 Kbps.  At the time, this was quite speedy, more than double the speed of the modems we had, and our smaller customers loved ISDN.  Because it was a dial-up technology, however, per minute rates applied.  This meant the line would time out and disconnect periodically to save costs.  When it was down and an outbound packet arrived at the router with the ISDN interface, the router would dial up the SP again.  The connection time was much faster than analog modems, but it still added latency which was annoying.

I don’t know if other regions did it, but we had a local hack to get around this.  Understanding the hack requires a little background on the phone systems of the time.  Two kinds of business phone systems were typically in use:  PBXs and key systems.  With a key system, every phone had an extension number, but no direct dial into it.  If you wanted to speak to the person at extension 302, you dialed the main phone number for the business, and either asked the receptionist to connect you, or else an automated system did it for you.  For outbound dialing, the user would either lift the handset and select an unused line from the pool of lines available, or perhaps dial 9 for the key system to connect them to the next available line.  PBXs, on the other hand, were used by large companies, gave each user their own phone line and allowed inter-office extension-to-extension calling, as well as direct dial from the outside world.  If my extension was 3202, I would have a direct dial phone number of, say, 415-555-3202.

Some companies instead opted for the phone company to do their internal switching.  This was known as a Centrex service.  The phone company provided hard wired analog phone lines to the customer, but enabled extension-to-extension direct dial.  Thus, if I was at extension 3202 and I needed to dial extension 3203, I could pick up the phone and just dial the four digits.  The phone company took care of routing it.

What does this have to do with ISDN?  We used to order Centrex service for our customers in the same Centrex group as their ISP. Thus, the customer’s ISDN line became an “extension” of the ISP’s Centrex group.  Not only could the customer then dial the ISP with four digits (not a big deal when the router is doing the dialing), but there were no toll charges on Centrex lines.  We used to nail the line up so it would never disconnect, and if it did for an reason, it would auto-redial.  And then we had dedicated Internet service on a dial-up line!

T1’s (E1’s elsewhere) were 1.544 Mbps, blazing fast at the time.  Unlike the single-pair ISDN line, T1’s were delivered on four wires, two for TX and two for RX.  I won’t get into the details of line coding on T1’s, which we all studied as junior network engineers.  T1 lines were truly dedicated, and provided a point-to-point connection from customer to ISP.  They were distance-priced, but I worked in San Francisco which is a small city, so it wasn’t usually a factor.  Because 1.544 Mbps was expensive for some customers, we had the option of ordering fractional T1s, fewer channels at a slower speed, but still faster than ISDN.  In the early days we had to terminate the T1 on an external CSU/DSU device, and then run a serial cable to the router, but eventually the CSU/DSU came integrated on the router interface card.

When I worked at the San Francisco Chronicle, we were providing Internet service via a T1 line terminating on a 2500-series router.  (The same one disabled by paint roller in this story.)  1000 users on a single T1 was painfully slow, and we made the decision to upgrade to a DS3 (T3) which ran at 45Mbps.  The interface for DS3 used two BNC coax connections.  I remember being amazed that the phone company could deliver service over coax, but it turns out that service into the building used fiber optics.  Inside the building we ran coax.  The run of coax from the basement to our 2nd floor data center was expensive, but the result was phenomenal.  The DS3, which we terminated on a brand new 7200vxr, was vastly superior to the crawling T1, and the effort paid off with our users.

DSL was groundbreaking.  There was nothing consumer-grade before that, and small companies could not even afford Internet connectivity.  I was one of the first home adopters of DSL.  The freshly-trained phone guy showed up at my apartment and installed a splitter box in the basement.  This was needed because residential service was ADSL, which multiplexed digital service on an analog line.  Unlike ISDN, which converted analog phone signal to digital, ADSL left the analog in tact, adding the digital part of the signal onto the higher frequencies.  The splitter box took the incoming phone line from the street and peeled off the high frequencies, providing an analog signal for telephones.  It then passed through the analog/digital mix intact to the modem, which just ignored the analog frequencies.  The phone guy then sat down with his toolbelt and tried to configure TCP/IP on my computer.  He gave up because he had no idea what he was doing.  I told him to leave me the IP addresses and I’d do it myself.  Eventually the telco would just send you an small filter to plug into each analog phone jack yourself, and they could turn on the service without sending a phone guy to rewire things.  Once DSL in its various forms came out, the Internet was available to the masses.  Of course, cable modems came shortly after.

We take for granted instant connectivity from every location on portable devices.  Once upon a time,  connectivity was only available at certain locations, often requiring dialing a service provider.  There was a real excitement as new technologies emerged for making connectivity faster and easier.  Now, of course, we just expect things to work and get angry when they don’t.

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Remote Access

As a part of my job at Cisco I’ve been looking into Zscaler and their offerings.  It started me thinking back to the early days of remote access, and I figured it would make a good topic for Netstalgia.

I wrote in the past about how bulletin board systems (BBSs) work, and in another article I resurrected my old BBS in an Apple II emulator.  In a nutshell, a computer with a BBS set up had a modem on it and users dialed in using their own modem over dial-up phone lines.  I’m not sure how many readers are young and don’t remember modems, and how many are dinosaurs like me, but as a reminder, modems connect computers to phone lines.  One modem is set to answer any call that comes in, and waits.  Then another user with a modem inputs the phone number of the other end into his software.  His modem dials out, the phone rings, and the other modem answers with a carrier tone.  Then the dialer responds and after some negotiation on the line, a connection is established and data is sent.

Now in my first job, at a small company in Marin California in the mid-1990’s, we had one computer set up as a dedicated remote access server.  It had a single modem with a single phone line, and ran Apple Remote Access server, since we were a Mac shop.  We only had one user with a laptop, the CEO, so when he traveled he would dial-in and be able to access basic functions like email and our file server.  There was no Internet access back then.

When I moved on to a consulting company, I did a few more industrial set ups.  Usually these involved remote access servers that were comprised of a bunch of modems and a LAN port.  The remote access server would accept a bunch of phone lines and then provide TCP/IP or AppleTalk connectivity to the network.  By this time users had Internet connectivity.  The Shiva LanRover is one example of this sort of device.

Shiva LANRover

When I worked at the San Francisco Chronicle, we had an Ascend Max which served this purpose.  The Max had two DS3 lines plugged into it.  It was the first time I had seen a DS3, and I remember being excited to learn the phone company could deliver a circuit over coax.  (It actually entered the building on fiber and went over coax from the MPOE.)  The DS3 was an ISDN PRI, with 24 dial-in phone lines multiplexed over a single digital circuit.  It took me months to find someone who had the password to the Max, and when I finally got in I found out that the second DS3 was unconfigured.  Users had been complaining about busy signals and all I had to do was change a few menu settings.

Ascend Max

Remote access dial-up was heavily used at the Chronicle.  Reporters filed their stories via modem.  VPN was just coming out, and I decided to replace the dial-up with VPN + dial-up.  A company called Fiberlink provided a dialer with a vast database of local Internet dial-up lines from a variety of carriers they contracted with.  Our users would pick a local phone line and then dial into it.  They then launched our Nortel VPN client to establish connectivity.  This saved us a fortune on 800-number charges, but our users hated it.  As a good senior guy, I did the initial design and left implementation to a junior guy.  I’m amazed he still talks to me.  (And he’s not junior anymore!)

Despite being a long-time Cisco guy, I never touched the Cisco remote access stuff.  I did use 2500-series routers with serial ports as terminal servers in the lab, but I never connected modems to them.  Still, when I passed my CCNP, one exam covered remote access and I needed to know a lot about modems.

Nowadays I rarely log into VPN.  Most systems I need to access can authenticate through our Zero Trust/SSO system without the need for a connection to Cisco’s network.  We’ve come a long way since the days of dial-up.  And while I said I missed wiring in another post, I sure don’t miss modem tones!

 

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How not to do Internet Connectivity

My first IT job was at a small company in Novato, California, that designed and built museum exhibits.  At the time most companies either designed the exhibits or built them, but ours was the only one that did both.  You could separate the services, and just do one or the other, but our end-to-end model was the best offering because the fabricators and designers were in the same building and could collaborate easily.  The odd thing about separating the functions was that we could lose a bid to design a project, but win the bid to build it, and hence end up having to work closely with a competitor to deliver their vision.

A museum exhibit we designed and built

The company was small–only 60 employees.  Half of them were fabricators who did not have computers, whereas the other half were designers and office staff who did.  My original job was to be a “gopher” (or go-fer), who goes for stuff.  If someone needed paint, screws, a nail gun, fumigation of a stuffed tiger, whatever, I’d get in the truck and take care of it.  However, they quickly realized I was skilled with computers and they asked me to take over as their IT guy.  (Note to newbies:  When this happens, especially at a small company, people often don’t forget you had the old job.  One day I might be fixing a computer, then the next day I’d be hauling the stuffed tiger.)

This was in the mid-1990’s, so let me give you an idea of how Internet connectivity worked:  it didn’t.  We had none when I started.  We had a company-internal network using LocalTalk (which I described in a previous post), so users could share files, but they had no way to access the Internet at all.  We had an internal-only email system called SnapMail, but it had no ability to do SNMP or connect beyond our little company.

The users started complaining about this, and I had to brainstorm what to do when we had virtually no operating budget at all.  I pulled out the yellow pages and looked under “I”, and found a local ISP.  I called them, and the told me I could use Frame Relay, a T1, or ISDN.  I had no idea what they were talking about.  The sales person faxed me a technical description of these technologies, and I still had no idea what they were talking about.  At this point I didn’t know the phone company could deliver anything other than, well, a phone line.  I wasn’t at the point where I needed to hear about framing formats and B8ZS line encoding.

We decided we could afford neither the ongoing expense, nor the hardware, so we came up with a really bad solution.  We ordered modems for three of the computers in the office:  the receptionist, the CEO, and the science researcher.  For those of you too young to remember, modems allow you to interface computers using an ordinary phone line.  We ordered a single phone line (all we could afford).  When one of them wanted to use the Internet, they would run around the office to check with the other two if the line was free.

A circa-1990’s Global Village modem

The reason we gave the receptionist a modem is amusing.  Our dial-up ISP allowed us to create public email addresses for all of our employees.  However, they all dumped into one mailbox.  The receptionist would dial in in the morning, download all the emails, and copy and paste them into the internal email system.  If somebody wanted to reply, the would send it to the receptionist via SnapMail and she would dial up, paste it into the administrator account, and send it.  Brilliant.

Needless to say, customer satisfaction was not high, even in those days.  Sick of trying to run IT with no money, I bailed for a computer consulting company in San Francisco and started installing the aforementioned T1s and ISDN lines for customers, with actual routers.

If ever you’re annoyed with slow Wi-Fi, be glad you aren’t living in the 1990’s.