Over the past week or two, I’ve heard about VoIP a bit more than usual, first with Adrian of Beat FM doing his thing over VoIP from Lis­more with FireFly/Freshtel, and then a lit­tle later, when Steve asked if I could join a convo with a guy called Dave to pro­vide some gen­eral Linux advice, as Dave had just installed the Aster­isk PBX soft­ware on a box (or, if you’re Steve, “com­puter”) and needed to SSH into it.

So, awareness/interest cat­a­lysts are there. I’d looked/heard about the Aster­isk soft­ware some time ago, but sort of wrote it off as not quite worth the effort. More recently, how­ever, we’ve been try­ing to get gen­eral ICT stuff sorted for the new place of res­i­dence, in a way that’ll let us cut costs a little.

Con­text: We’re a house­hold of six, and about that many func­tional com­put­ers (give or take two depend­ing on what­ever) at any one time. We’ve got three mobiles (the sib­lings don’t, yet), and had one land­line (there are two lines where I’m stay­ing, one listed, one not — but that’s only tem­po­rary so it doesn’t count), which was used for voice and data. We’d had HFC TV/data cable run into our house pre­vi­ously, but didn’t use it for either CATV or Internet.

So Dad’s want­ing to fig­ure out a way to get rid of the land­line, or at least cut the costs of hav­ing it there, see­ing we’re going to be using Tel­stra Cable (and there­fore don’t need the cop­per). Unlike the other major telco here in Aus­tralia, Optus, Tel­stra don’t run tele­phony over HFC even if it’s installed at the premises — most likely as a busi­ness deci­sion (they’ve already made con­sid­er­able out­lay in installing and main­tain­ing a cop­per net­work, which they’re going to try and make peo­ple think they con­tinue to need for as long as humanly pos­si­ble — they get line rental, LSS, DSLAM port fees and (from some cus­tomers) ADSL rev­enue all off the same sin­gle service!)

Dad’s idea: Use capped local call costs with mobile tele­phony provider, Orange, to elim­i­nate need for cop­per. The lim­i­ta­tion? Max­i­mum 10 minute calls before we need to redial/pay stan­dard rates, and inabil­ity to use data/fax (well, okay, not com­plete inabil­ity… but suf­fi­ciently dif­fi­cult). Yeah, there are caps with other providers like Voda­fone and 3, but even $59 caps would be more/about the same than/as we’d oth­er­wise spend.

Josh’s idea: True VoIP (not soft­phone) hard­ware solu­tion, with (at least one) DID line, run­ning over HFC Inter­net. Dad had sug­gested VoIP pre­vi­ously, but I think I’d kind of assumed he was talk­ing about doing it on the cheap (so, crappy desk­top call­ing soft­ware — some­thing like Fire­Fly, which is fine just for fun, but not if you’re actu­ally using it to make calls regularly) — and basi­cally said “no” out­right. Essen­tially this solu­tion would either involve ded­i­cated hard­ware or an Aster­isk server con­nected to an Inter­net Tele­phony Provider IAX.

All this is fine. It’s all mak­ing sense. It’s just that there are waaaaaay too many new TLAs for my com­fort — I’ve made an effort to use acronym markup on most new terms in this post, but it really needs a glos­sary at the end! If I can be both­ered, I’ll do that when this post finishes…

Basi­cally, every­thing is per­fectly nor­mal thus far. There’s no really dif­fi­cult con­cepts to grasp — it’s just “plug in a Grand­stream ATA, hit the web inter­face, sign up for an account with a provider and start mak­ing and receiv­ing calls”. But you know, that’d be bor­ing. That’d really suck. Why? Well, when you’ve got Cat5 com­ing out of your ears between rooms, you may as well use it.

Aster­isk will man­age call­ing, call rout­ing, call wait­ing, voice­mail, DND, hold music, diverts, CID and every­thing else under the sun. Even if there’s only one DID num­ber, it’s still pos­si­ble to have mul­ti­ple incom­ing lines per num­ber for a nom­i­nal fee (with ATP it’s $AU5.50 per month inc. GST), and there’s no limit (band­width aside) to the num­ber of simul­ta­ne­ous out­go­ing calls that are pos­si­ble (although, accord­ing to Dave, who is also on Tel­stra cable, things start to get painful above 4 calls). The eas­i­est way to use phones with Aster­isk is with VoIP SIP tele­phony devices, which plug into stan­dard RJ45 net­work sock­ets and con­nect directly to the server using data. Why not do this? Well, for one, you lose all the func­tion­al­ity of any ana­logue tele­phony equip­ment you might have lying around.

So how do you get this kind of equip­ment to work? This is where the more con­fus­ing and dif­fi­cult to remem­ber acronyms (at least for me) set in. Aster­isk can inter­face with stan­dard PSTN lines, func­tion­ing as a non-VoIP PBX sys­tem with the req­ui­site hard­ware installed — namely, FXS and FXO mod­ules. Stan­dard ana­logue equip­ment (phones, fax machines, etc.) plugs into FXS ports on the PBX, whilst PSTN lines con­nect into FXO ports. Digium, prin­ci­ple spon­sor of the Aster­isk project, have a great expla­na­tion of the rela­tion­ship between the Aster­isk PBX and FXS/FXO mod­ules, com­plete with diagrams.

We’ve only really got one ana­logue phone worth keep­ing, which is a Uniden cord­less thing with two hand­sets (base sta­tion and sep­a­rate charger for the sec­ond hand­set), and that’s what I’d inter­face via an FXS to the PBX, as well as a sec­ond FXS for a fax machine. I’m a tad uncer­tain as to how well fax data will work over VoIP, but that’s a ques­tion for the Fak­tor­Tel sup­port team when it comes to actu­ally sign­ing up for stuff.

There is only one other hes­i­ta­tion sur­round­ing VoIP, and that’s the issue of emer­gency call­ing (“000” in Aus­tralia, “911” for US… I don’t know about the rest of the world, sorry). If there’s a power fail­ure or the Inter­net goes out, how do we make calls to the out­side world in the event of an emer­gency? Well, logic pre­vails — in a house­hold with three mobiles on two dif­fer­ent net­works (three if you’re count­ing roam­ing), chances are that at least one of them will be work­ing fine in the event of an emer­gency… and if they’re not, then the tele­phony net­works in Aus­tralia are prob­a­bly so stuffed that even if we were call­ing over a PSTN line, it’d prob­a­bly not work either!

So there’s an essay about VoIP for you. And what I sort of want to do with it. I haven’t for­got­ten about the acronyms, by the way: here’s a list of terms for you…

Glos­sary

ADSL

Asym­met­ri­cal Dig­i­tal Sub­scriber Line

ATA

Ana­logue Tele­phone Adapter

CATV

Cable TV

CID

Caller Iden­ti­fi­ca­tion

DID

Direct In-Dial

DND

Do-Not-Disturb, the abil­ity to dis­able ring­ing on a cer­tain phone/line

DSLAM

Dig­i­tal Sub­scriber Line Access Multiplexer

FXO

For­eign Exchange Office, a port into which PSTN lines are connected.

FXS

For­eign Exchange Sta­tion, a port into which hand­sets and ana­logue equip­ment is connected

HFC

Hybrid Fibre (over) Coaxial

IAX

Inter-Asterisk Exchange

ICT

Infor­ma­tion and Com­mu­ni­ca­tion Technology

LSS

Line Spec­trum Shar­ing, ser­vice required to run tele­phony and ADSL over the same copper

PABX

Pri­vate Auto­matic Branch eXchange

PBX

Pri­vate Branch eXchange, gen­er­ally a con­trac­tion of “PABX”, as man­u­ally switched exchanges are related to dinosaurs.

POTS

Plain Old Tele­phone Sys­tem, also PSTN

PSTN

Pub­lic Switched Tele­phone Network

SIP

Ses­sion Ini­ti­a­tion Pro­to­col, an IETF stan­dard pro­to­col for ini­ti­at­ing con­nec­tions for inter­ac­tive plat­forms, includ­ing VoIP

SSH

Secure SHell

VoIP

Voice over I.P. (“Inter­net Protocol”)

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