TIA/EIA-562 is an unbalanced, unidirectional, point-to-point electrical standard designed to extend RS-232 compatibility to lower-supply-voltage environments such as battery-powered and office equipment operating from 3.3 V or 5 V rails. It defines electrical characteristics only — it is not a complete interface standard and is intended to be referenced by higher-level standards; most notably, EIA/TIA-561 (the 8-position RJ-45 RS-232 interface) cites TIA/EIA-562 for its electrical levels. The standard is fully interoperable with TIA/EIA-232-F devices, sharing the same ±3 V receiver thresholds, but its maximum capacitive load of 1000 pF (versus RS-232’s 2500 pF) implies shorter cable runs and, in practice, caps practical speed/distance combinations. No connector pinout is defined by TIA/EIA-562 itself.
Notes
Driver loaded output voltage (into 3 kΩ) must be at least 3.7 V — lower than RS-232’s equivalent but sufficient to cross the ±3 V receiver threshold.
Maximum capacitive load is 1000 pF, compared with 2500 pF for TIA/EIA-232-F, meaning cable lengths must be kept shorter for a given data rate.
Receiver thresholds of ±3 V are identical to TIA/EIA-232-F, ensuring interoperability with RS-232 equipment.
Transition time is controlled; maximum driver slew rate is ≤ 30 V/μs.
Driver output resistance when powered off is ≥ 300 Ω, protecting against bus contention.
The electrical specifications listed below are drawn directly from the standard:
- Driver Loaded Output Voltage (Min. Level) ≥ 3.3 V
- Driver Open Circuit Output Voltage ≤ 13.2 V
- Driver Loaded Output Voltage (3 kΩ) ≥ 3.7 V
- Driver Short Circuit Current ≤ 60 mA
- Driver Transition Time Controlled
- Maximum Driver Slew Rate ≤ 30 V/μs
- Driver Output Resistance (Power Off) ≥ 300 Ω
- Receiver Input Resistance 3 kΩ to 7 kΩ
- Maximum Receiver Input Voltage ±25 V
- Receiver Thresholds ±3 V
References
- Fundamentals of RS-232 Serial Communications — Analog Devices (formerly Maxim Integrated); covers EIA/TIA-562 voltage levels and capacitive load limits.
- AN-216: Summary of Well Known Interface Standards — Texas Instruments; tabulates TIA/EIA-562 alongside TIA/EIA-232-F, TIA/EIA-423-B, TIA/EIA-694, and TIA/EIA-422-B.
- AN-917: Popular Connector Pin Assignments for Data Communications — Texas Instruments; notes EIA/TIA-561 references EIA/TIA-562 for electrical levels.