Touch Memory & iButton FAQ

DS1990A is the original Dallas/Maxim part designation. TM1990A is an alternative read-only 64-bit ROM key using the 1-Wire interface. A shared interface alone does not confirm acceptance by your system: check the exact reader/controller model and firmware, and validate ID reading and registration with a sample before ordering in bulk.

Yes. RW1990 has a programmable, rewritable ID. The writer must support the supplied blank version and write routine; the model name alone is not enough. Confirm the write-cycle specification for the quoted version, then test writing, rewriting and reading with your own test ID on your writer and target system.

TM1990A-F5 is a read-only 1-Wire ROM key in an F5 package. Check the reader/controller model, firmware and mechanical fit, then test ID reading and registration on the actual system. Send those device details with your inquiry so we can help check the proposed configuration.

For the original DS1990A, the ROM contains a family code, serial number and CRC. A family-code table is a format reference, not proof of the manufacturer, exact variant, ID uniqueness or system acceptance. Check the supplied part documentation and read a sample.

Match the key and reader mechanically, including any magnetic retention requirement. Request the supplied version’s drawing and confirm seating, contact and retention with a sample. Do not assume price or fit from the magnetic/non-magnetic label alone.

Touch Memory requires electrical contact with a reader; RFID uses a radio interface. Compare the exact credential and reader formats, physical installation, wear and system security requirements. A contact interface alone does not guarantee resistance to copying or relay attacks.

TM08v2 supports multiple format families, including Dallas, Cyfral and Metakom. Acceptance depends on the specific blank version, writer, panel and firmware, so confirm the required format and test samples on each target system. For a one-time-programmable credential, check the exact OTP version and its write-lock behaviour. OTP prevents rewriting that blank; it does not by itself prevent its readable ID from being copied to another device.

Lifetime, operating temperature, sealing and contact endurance must be confirmed for the supplied version. We do not currently publish verified ratings for TM1990A-F5 or RW1990 on these points. Request the relevant specification and evidence, then agree sample checks for your installation; original DS1990A ratings do not transfer automatically.

The following terms apply to TM1990A-F5 and RW1990 only. TM1990A-F5: Reference price US$0.25–0.50 per piece; Bulk order minimum 500 pieces. RW1990: Reference price US$0.26–0.55 per piece; Bulk order minimum 500 pieces. 10 free sample pieces, ready in 3 days; you pay sample shipping. Final pricing depends on quantity, version, marking and packing. Other quantities and special requirements, their preparation times, shipping charges, transit time and taxes are confirmed with your quote. For other models or custom ROM ranges, colours, marking and packing, share your requirements so we can confirm feasibility and ordering terms.