Editing Smart card (section)

====Components====

Complex Cards can incorporate a wide variety of components. The choice of components drives functionality, influences cost, power supply needs, and manufacturing complexity.

=====Buttons=====

Depending on Complex Card types, buttons have been added to allow an easy interaction between the user and the card. Typically, these buttons are used to:
* Select one action, such as which account to obtain the balance, or the unit (''e.g.'' currency or number of trips) in which the information is displayed,
* Enter numeric data via the addition of a digital keypad,
* Enter text data via the addition of an alphanumeric keyboard.

While [[Membrane keyboard|separate keys]] have been used on prototypes in the early days, capacitive keyboards are the most popular solution now, thanks to technology developments by AudioSmartCard International SA.<ref>{{cite web |title=Infogreffe – AudioSmartCard International SA |url=https://www.infogreffe.com/entreprise-societe/391975125-audiosmartcard-international-sa-750196B12386.html |website=Infogreffe |publisher=French corporate register |access-date=12 June 2021 |archive-date=1 May 2021 |archive-url=https://web.archive.org/web/20210501035129/https://www.infogreffe.com/entreprise-societe/391975125-audiosmartcard-international-sa-750196B12386.html |url-status=live }}</ref>

The interaction with a capacitive keyboard requires constant power, therefore a battery and a mechanical button are required to activate the card.

=====Buzzer=====

The first Complex Cards were equipped with a buzzer that made it possible to broadcast sound. This feature was generally used over the phone to send identification data such as an identifier and one-time passwords (OTPs). Technologies used for sound transmission include DTMF ([[dual-tone multi-frequency signaling]]) or FSK ([[frequency-shift keying]]).

Companies that offered cards with buzzers include: 
* AudioSmartCard, 
* nCryptone,<ref>{{cite web |title=Bloomberg – nCryptone |url=https://www.bloomberg.com/profile/company/758050Z:FP |website=Bloomberg |access-date=12 June 2021 |archive-date=19 October 2021 |archive-url=https://web.archive.org/web/20211019090211/https://www.bloomberg.com/profile/company/758050Z:FP |url-status=live }}</ref>
* Prosodie,
* Société d'exploitation du jeton sécurisé – SEJS.

=====Display=====

Displaying data is an essential part of Complex Card functionalities. Depending on the information that needs to be shown, displays can be digital or alphanumeric and of varying lengths. Displays can be located either on the front or back of the card. A front display is the most common solution for showing information such as a One-Time Password or an electronic purse balance. A rear display is more often used for showing a Dynamic Card Security Code (DCSC).

Displays can be made using two technologies: 
* [[Liquid-crystal display]] (LCD) : LCDs are easily available from a wide variety of suppliers, and they are able to display either digits or alphabetical data. However, to be fitted in a complex smart card, LCDs need to have a certain degree of flexibility. Also, LCDs need to be powered to keep information displayed. 
* [[Liquid-crystal display#"Zero-power" (bistable) displays|Bistable displays]], also known as [[Ferroelectric liquid crystal display]]s, are increasingly used as they only require power to refresh the displayed information. The displayed data remains visible, without the need for of any power supply. Bistable displays are also available in a variety of specifications, displaying digits or pixels. Bistable displays are available from E Ink Corporation<ref>{{cite web |title=E Ink |url=https://www.eink.com/index.html |website=E Ink |access-date=12 June 2021 |archive-date=30 July 2021 |archive-url=https://web.archive.org/web/20210730164908/https://www.eink.com/index.html |url-status=live }}</ref> among others.

=====Cryptoprocessor=====

If a Complex smart Card is dedicated to making cryptographic computations (such as generating a one-time password) it may require a [[secure cryptoprocessor]].

=====Power supply=====

As Complex Cards contain more components than traditional smart cards, their power consumption must be carefully monitored.

First generation Complex Cards require a power supply even in standby mode. As such, product designers generally included a battery in their design. Incorporating a battery creates an additional burden in terms of complexity, cost, space and flexibility in an already dense design. Including a battery in a Complex Card increases the complexity of the manufacturing process as a battery cannot be hot laminated.

Second generation Complex Cards feature a battery-free design. These cards harvest the necessary power from external sources; for example when the card interacts in a contact or [[Electromagnetic induction|contactless]] fashion with a payment system or an NFC-enabled smartphone.  The use of a bistable display in the card design ensures that the screen remains legible even when the Complex Card is unconnected to the power source.