SeaLevel Route 56 User Manual page 21

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 the signals are
differential, in RS-530A the signals 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 type of interface
circuits, Data Terminal Equipment (DTE) and Data Circuit-Terminating
Equipment (DCE). The Sealevel Systems adapter is a DTE interface.
Sealevel Systems ROUTE 56 Page 18