There are a number of redundant pieces of technology involved in the headware. It only makes sense that it be possible to obtain pieces of cyberware that combine the standard functions at a lower Essence cost, at the extra proviso of having to buy things in a package. A few prices and Essence costs of items may be affected in this attempt to rationalize the available cyberware.
Shadowtech gives us most of the pointers we need. The sourcebook points out:
|Simsense input and cybernetic command||0.05||250¥|
|25 DFR I/O||0.05||250¥|
|Level 0 I/O subprocessor||0.05||500¥|
|Level 0 encephalon (datasoft link)||0.10||750¥|
|Synthesizer command interface||0.10||750¥|
|Radio frequency transceiver (Commlink-I)||0.30||1200¥|
|Synthlink radio packet encoder||0.10||550¥|
|Cybernetic command processing||0.05||60,550¥|
These can be put together to get appropriate cyberware. A standard datajack is a simsense input and cybernetic command processor, 25 DFR I/O, and a level 0 I/O subprocessor, which sums to 0.15 Essence and 1000¥. A chipjack is just a softlink-1, which is 25 DFR of I/O and a level 0 Encephalon, summing to 0.15 Essence and 1000¥. A synthlink— SRII style, not Shadowbeat style— is a synthesizer command interface and 25 DFR, making for 0.15 Essence and 1000¥. (I was able to infer that it’s 0.2 Essence from a character in Paradise Lost.) So far, so good.
An omnijack is a jack that combines the functions of datajack and chipjack: it can be one or the other, depending on what you plug into it, and I believe it to be one of the most common pieces of cyberware in the world of Shadowrun. It’s 25 DFR of I/O, the level 0 I/O subprocessor, the simsense input and cybernetic command, and the level 0 Encephalon, summing to 0.25 Essence and 1750¥. A version that does all that and talks to music synthesizers will run you 2500¥ and 0.35 Essence.
Things begin to get iffy when you get into the headware radio department.
A headware telephone is a Commlink-I with subdermal speakers and a subdermal microphone, summing to 0.5 Essence and 3700¥. A headware radio receiver should be the same without the microphone at 0.4 Essence and 1850¥. (I can’t figure out why a radio transceiver has a different cost from a telephone, which is basically just a radio transceiver.) Getting a Commlink-II through -X should replace the other toys, rather than getting the bonus mentioned in the Street Samurai Catalog. (It just doesn’t make sense, otherwise.) A cybercomm link is a Commlink-I that has some dedicated processing hardware that does the same job that a cyberdeck does when a decker is running through Direct Neural Interface. It converts neural impulses into words, and converts sound from the radio into a simsense signal.
(The Shadowbeat version of the synthlink is wireless and costs half an Essence point; it’s a synthlink hooked up to a radio transceiver with 0.1 Essence worth of hardware invested in encoding and decoding the synthlink signals for transmission over the airwaves.)
You should never need more than one set of wires going into the skill-oriented part of your brain. If you have an Encephalon installed at the same time as your softlink, you should be able to save 0.10 Essence.
If you have a datajack and a cybercomm link put in at the same time, the cybercomm link should be able to access the simsense and cybercommand circuitry of the datajack, saving you 0.05 Essence.