Here are some likely questions that are asked in relation to ISDN DOV (Data-Over-Voice). While the information given is specific to certain circumstances, by all means please contact us for other queries not listed here.

1. IMPORTANT : How can I ensure that DOV is working?

To give yourself peace-of-mind when first adopting DOV using a NETjet ISDN modem, there are a number of things that we strongly advise you to check to ensure that you avoid any unexpected time-charged phone bills ...

(a) Don't forget to prepend the dialled number with a 'V' (upper or lower case).

(b) If you are a Windows user, in your Dialup Networking icon make sure you DO NOT have the box ticked for "Use area code and Dialing Properties" as this will insert an area code in front of the "V" and your call will not be a DOV call !

(c) If you are using SmoothWall 0.9.9, make sure you only load up to SmoothWall patch 2, and then apply our DOV patch. Do not install any patches after patch 2 as this will remove our DOV patch.

(d) If you are using Linux (including SmoothWall), check the kernel log file /var/log/messages : the CALL TYPE (the Bearer Capability i.e. Data or Voice) for all outgoing calls is logged in this file each time the system makes a call. MAKE SURE IT IS VOICE.  If the DOV patch has not been installed or applied correctly, the CALL TYPE message will not appear at all. A correct DOV patch install will generate one of the following messages:

   "Call  type is DOV (Data over Voice)"
    or
   "Call type is DATA"

(e) Always check the CALL TYPE after installing new drivers or any patches - this applies to all operating systems! A good way to do this is to call your home phone number or mobile number and make sure that it rings. If it DOES NOT ring then you are using a timed data call.

(f) We recommend that you use EON's DOV ONLY access number. That way if you are misconfigured for Data calls, you can't connect to EON.

(g) Subscribe to online billing from Telstra - it's free and you can check yesterday's phone bill here

ISDN DOV in a NETjet-S provides you with a 64K/128K digital modem to EON, at least 40% faster (270% if you use 2 channels!) than the best performance that can be achieved from a 56K analogue modem. DOV is the transmission of computer data over a voice line, and allows users to take advantage of any price differential between voice and data calls when making dialup calls from their computer system. For example, for ISDN home users this differential is now 18c untimed for voice calls versus $1 per hour for data calls (plus GST) when using the ONRAMP HOME HIGHWAY product from Telstra.

A more familiar example of DOV is the traditional analogue modem, which uses PSTN DOV - calls are charged at the same price as a normal telephone voice call. With a 56K analogue modem, which operates asynchronously, users only achieve a maximum of about 40K actual throughput. With a NETjet-S you can now achieve the full 64K digital to EON (some ISPs only allow 56K digital, still some 40% faster than an analogue modem)! And most users experience much lower throughput with 56K analogue modems due to line quality.

For ISDN services, Telstra has always used timed call charges in Australia - until now. With the ONRAMP HOME HIGHWAY product, voice calls are currently charged at the standard 18c call rate and are not timed. Therefore, with ONRAMP HOME HIGHWAY you can now choose to connect your computer using either PSTN or ISDN DOV, at the same 18c untimed call rate.

You can even check your recent call costs on-line - simply register your account with Telstra's Call Preview facility!

A 56K analogue modem operates asynchronously and includes a start and stop bit with every 8-bit character. For example, a 56K modem will normally operate at a much lower speed (say 44K, 33K or even 28K if the line quality is poor), and then you need to subtract 20% from that because of the start and stop bits.

With ISDN (and DOV) you get the full digital bandwidth every time. Not to mention a logon in seconds rather then 30+ seconds! And less dropouts! And the ability to combine 2 channels for 112 or 128K.

The following diagram shows the performance advantages : (i) is a standard 56K analogue modem on a normal telephone connection (PSTN). If you then have ORHH installed, you can still connect via your 56K analogue modem and you will generally get about 25% faster performance and more reliability - see (ii).

However, if you install a NETjet ISDN modem in your computer instead, and connect the NETjet to ORHH, you can place a DOV call to your ISP at a true 64K digital rate (iv) - an 87% performance increase. Or, for the price of 2 telephone calls, you can achieve 128K - see (vi) - a 270% improvement over your original 56 analogue modem!

EON have equipment which can allow ISDN DOV connections at the full 64/128K, exactly the same as a normal ISDN data connection (ie. non-DOV). Depending on their access equipment, however, some ISPs only allow incoming DOV calls at 56K digital (or 112K if you multilink the two ISDN channels) - see (iii) and (v) - this still provides an extra 65% (or 230%) performance increase.

If you connect two computers via a NETjet at each end, you can also achieve the full 64K or 128K using DOV - as in (iv) and (vi).

As well as faster throughput, you can connect in seconds using a NETjet and DOV - see the next diagram. No more hiss, crackle and pop for 30+ seconds with your old analogue modem!

And what are the line costs for DOV? Well, no more than your old 56K analogue modem!
Just 18c (+GST) for a local, untimed 56K or 64K digital call, and 36c (+GST) for a local, untimed 112K or 128K call.
Say you average 1-hour of connection time to your ISP every night, for a month using 64K DOV - then you will pay only 31*18c = $5.58 plus GST! Or just $11.16 plus GST for a 128K connection!

ADSL and Cable are serious alternatives, but have a number of drawbacks.

They are considerably more expensive. With ONRAMP HOME HIGHWAY you pay for line rental which for 2 telephone lines is very reasonable at $39/month less $5 in calls (plus GST). Seeing as most households pay for at least 1 telephone line rental anyway, the incremental cost for ONRAMP HOME HIGHWAY is small. You get a second telephone line - useful if there are teenagers in the house!

ADSL and CABLE require lengthy contracts (up to 18 months long). With ONRAMP HOME HIGHWAY it is user-pays for all calls - great if you take a months holiday.

ISDN is a very flexible service. Up to eight addressable devices can be installed on the ISDN S-bus. These may include faxes, computers and telephones. With the HOME HIGHWAY, it is very handy to have your fax installed on the second line. Another key feature of ISDN is that it can be used point-to-point, for example when telecommuting to work, or sending video camera output to a security firm. Both Cable and ADSL are designed primarily for net access and email.

ADSL and Cable are not as widely available as ISDN.
The rollout of Cable in Australia appears to have ended.
A recent Telstra press release stated that ADSL would be available to 90% of Australian homes and businesses by mid-2002, so over the next 2 years many users will not have ADSL availability.

Performance of Cable is generally higher than ISDN, but suffers as the number of Cable users in your street increases.
Performance of ADSL is much better but is very sensitive to distance from the local exchange. Judging from international experience, expect a few teething problems.