®
SP503
Application Note
s
DTE and DCE configurations with
the
SP503
s
Connecting the
SP503
to a DB-25
connector in DTE and DCE modes
s
Implementing V.35 with the SP503
s
Creating extra single-ended and
differential channels with the
SP503
using the SP310A and SP485
s
Using external supplies with the
SP503
Due to its flexibility and programmability,
the
SP503
has been finding its way into
many new networking products. The
SP503
offers an excellent replacement for discrete
solutions on X.25 implementations for frame
relay systems, multi-protocol routers and
other WAN products where many designs
run various modes such as RS-232,
RS-422, V.35 or V.36.
For RS-232, the older bipolar 1488 and
1489 parts, or even the newer MAX230 or
SP230 series have traditionally been used.
For RS-422 or RS-485, the 26LS31,
26LS32, 3488, and 3489 have been seen in
many designs. These parts have been also
used for V.35 but with external termination
resistors. For a typical design, four RS-232
chips would be used for a complete
RS-232 port, four RS-422 chips for an
RS-422 port and four chips for V.35 with an
external resistor network. Port programma-
bility would require relays or switches so
that software lines can control whether
RS-232 is active or RS-422 is active. The
relays increase board capacity as well as
cost to the design.
The
SP503
solves board space and cost
problems by offering a single packaged part
that supports various protocols and also
offers software programmability to the port.
Typical discrete solution vs. the SP503
SP503AN
SP503 Application Note
© Copyright 2000 Sipex Corporation
1
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