Rs-530 / 530A - SeaLevel ACB-MP.PCI User Manual

Appendix C - Electrical Interface

RS-530 / 530A

RS-530 (a.k.a. EIA-530) compatibility means that RS-422 signal levels are met, and the pin-out for the DB-25
connector is specified. The EIA (Electronic Industry Association) created the RS-530 specification to detail the
pin-out, and define a full set of modem control signals that can be used for regulating flow control and line status.
The major difference between RS-530 and RS-530A lies in the modem control interface signals. In RS-530 all
signals are differential, in RS-530A signals DTR, DSR, DCD are single ended. The RS-530 specification defines
two types of interface circuits, Data Terminal Equipment (DTE) and Data Circuit-Terminating Equipment (DCE).
The Sealevel Systems adapter is a DTE interface.
V.35
V.35 is a standard defined by ITU (formerly CCITT) that specifies an electrical, mechanical, and physical interface
that is used extensively by high-speed digital carriers such as AT&T Dataphone Digital Service (DDS). ITU V.35 is
an international standard that is often refereed to as Data Transmission at 48 Kbps Using 60 - 108 KHz Group-
Band Circuits. ITU V.35 electrical characteristics are a combination of unbalanced voltage and balanced current
mode signals. Data and clock signals are balanced current mode circuits. These circuits typically have voltage
levels from 0.5 Volts to -0.5 Volts (1 Volt differential). The modem control signals are unbalanced signals and are
compatible with RS-232. The physical connector is a 34-pin connector that supports 24 data, clock and control
signals. The physical connector is defined in the ISO-2593 standard. ITU V.35 specification defines two types of
interface circuits, Data Terminal Equipment (DTE) and Data Circuit-Terminating Equipment (DCE). The Sealevel
Systems adapter is a DTE interface.
Sealevel Systems ACB-MP.PCI Page 11