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Tech Stuff

The Tech Info Pages are a collection of stuff (authentic tech term) that we have found useful over the years (see also our tech links pages).

Web Stuff Various information on Server Side Includes, CSS pop-out menus, DHTML and CSS notes, PHP4, regular expressions, Browser ID strings, HTML5 page conversion (our experience) and other stuff.
IP Address From our Cheap Tricks Dept. Your Browser ID and IP address. Woopdeedoo.
Open Guides Our first Open Guide tries to unravel the mysteries of installing and running (and even understanding) DNS. Our second guide struggles with LDAP (doesn't everybody).
Audio Visual Stuff Bit of a rag-bag of stuff on Digital Audio (some video), formats, principles of Digital Audio and common frequency ranges, noise levels and other essential - if arcane - stuff you will need if you get into this subject seriously. Now includes an acoustic calculator, stuff on equalization, using the FFT (mathless stuff - but still horrible) and some primers on sound (harmonics, fundamentals, partials, ADSR envelopes - but quietly, very quietly) and digital sound (time domain, frequency domain). Oh, and yet another glossary on the subject.
IP Calculators We regard Javascript as one of those necessary evils. So we slapped together a Javascript IPv4 Calculator and an IPv6 Calculator. Lets you do all kinds of really stupid things with IP addresses, subnets etc. If you are into DNS then these versions (IPv4 and IPv6) will even generate all kinds of delegation and reverse DNS zone file skeletons. Why did we do this? Good question.
Wiring Stuff Collection of cable pin-outs (RS232, V.35 etc), NULL Modems, LAN wiring standards, USB, telephone wiring standards, cable information. Now includes some PC stuff, for example, DIN and Mini-DINs, monitors etc..
Survival Guides We use a lot of software and we forget stuff. When you find yourself, for the third time this week, entering the wrong command into the wrong software for the wrong reason it's time to do something. We tried to bring together in a single page all the stuff that we (perhaps, you too) need on a regular basis. The current ones cover MySQL, Postfix, Cron, cryptography, TLS/SSL, X.509 certificates (including self-signed worked examples), ASN.1 and updating FreeBSD using a variety of methods. Mostly eye-wateringly boring.
Display Stuff Screen/display/monitor interfaces and resolutions are geting a little complicated these days. But is the VGA connector dead yet?
PC Stuff We get confused real easy. This is our attempt to keep a modest handle on all that USB, Firewire, DIN, IDE/EIDE/SATA stuff.
Protocol Stuff Ragbag of protocol information including frame formats and some backgrounders. Includes TCP/IP (UDP and ICMP), 802.3 LAN and VLAN, IP classes and CIDR, IPv6, some VoIP stuff, Video conferencing, SS7, SIGTRAN, H.323, SIP, MGCP (MEGACO) and even the now ancient ISDN protocols.
SS7/SIGTRAN Stuff Some material on SS7 and SIGTRAN. Includes a walk through the alphabet soup of SS7 and SIGTRAN, layer primitives, SIGTRAN stacks and applicable standards. Fun stuff really.
Wireless Stuff Collection of stuff about 2.4GHz and 5.8 GHz Wireless, wireless backgrounders, definitions of decibel, our wireless link calculators (budgets, free-space loss, fresnel zones, system power, watts to db conversion etc.), links to some heavy stuff, 802.11 formats, MAC layer etc. Crammed with smutty talk about decibels, DPQSK and power budgets. Ooof. Be still my beating heart.
ASCII Stuff Lots of places to find ASCII tables but we always forget 'em. In case you do as well here is a list of ASCII characters. And IA5 which is almost the same. And a mercifully short character code overview. An apparently simple subject which turns out to be brutally complicated - well to our modest brains.
Data Rates Definition of Telecom Data Rates covering T1, E-5 (CEPT5), OC-3, STS-48 etc., etc.
Telephony Stuff GSTN Network Tones, ring patterns, E&M signaling (North America and RoW)
Mechanical Stuff Even us electronic guys need to know which screws to use. Screw thread sizes, head types etc.
Language Stuff Some information about PHP, Java, C++ (WxWidgets) and Ruby. Nominally, we moved our development methodology to Ruby some years, but then came the fork. We still like the language but why do they do these things? Python forked 6 years ago, still have two versions, and probably still will have at the turn of the next millenium. Ruby has a much smaller user base (and one less with us gone - not that you'd notice) so they might just get away with a 20 year transition but it's still a real problem. We're pragmatists not purists. Consequently, we subscribe to the hammer theory of software. We learned to use a hammer years ago and while the techology used to manufacture (implement) hammers has changed radically over the years, last time we checked, hammers still work the same way. But who knows, maybe, a couple of thousand years ago, there were guys like us complaining when they introduced the handle for the hammer.
DOM Stuff Collection of information (now pretty ancient) about the W3C DOM including the beginning of our in-house reference section.
CSS Stuff There is a lot more to CSS than getting rid of all those stupid font tags. We missed the whole point. This section documents our contrite journey, starting in 2003, to a Better Place™. Including CSS based liquid layouts and pop-up, pop-down, drop-down and drop-dead CSS based menus.
Security Stuff Some information about security. Mostly email, anti-spam, and advice on healthy email habits.
Howto Stuff Paint-by-numbers information about certain topics. We just replaced our Primary Domain Controller (PDC) with a Samba3.x + LDAP configuration. We found it all horribly confusing to configure - but it works like a dream. We also just moved to a FreeBSD 5.x Firewall + NAT + DNS configuration for customer installations. The howto describes roughly what we did. We'll add more as we stumble through a series of major system upgrades. In the meantime we've provided a couple of guides on DNS and LDAP.
Electronic Stuff Includes a Glossary of electronic terms, information on 3.3V and 5V isolation, BDM interfaces for both the PowerPC and ColdFire ranges. Pretty long-in-the-tooth stuff these days, but it may give you a chuckle as a minimum.
RFC Stuff RFCs by topic. All the RFCs relevant to a particular topic, for example, IPSec, NAT. We rarely update this page these days. Iindeed, like us, we should probably retire the page but it may be of some use in getting started on a particular subject. We actively update specific topics - DNS, LDAP, IPv6 and TLS/SSL.

Problems, comments, suggestions, corrections (including broken links) or something to add? Please take the time from a busy life to 'mail us' (at top of screen), the webmaster (below) or info-support at zytrax. You will have a warm inner glow for the rest of the day.

Tech Stuff

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