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RS-232 Products

CPS - Products


Provides Highly Secure Access and Easy RS-232 Port Selection


232-PSS Picture


232-PSS Application Diagram


  • Hardware and Software Independent
  • Data & RS-232 Signals Pass Transparently
  • No Band Pass Limitation
  • Broadcast Data to All Ports
  • Outbound Call Contention Too
  • Use Standard UTP Cable for RS-232
  • Use for Maintenance Port Access
  • Optional Remote Programming
The 232-PSS is similar to common remote code activated software controlled switches that allow a caller to select up to 8 different RS-232 ports at a remote location. However, the 232-PSS provides automatic port selection along with a very high level of caller authentication and a lower cost alternative.

This unique concept is accomplished through the interaction of a unique matchbox sized hardware KEY connected to the analog side of the caller's modem and the 232-PSS. The authentication handshakes and port selection occur within one second of the receiving modem going off hook.

Inbound calls without the proper Secure Access KEY are simply aborted. There are over a billion handshake combinations that change with each call. The port selection (1-8) is made via a manual rotary switch that is also on the caller's KEY.

The authorization and setup occur very quickly; long before the modems are trained. There are no passwords or cumbersome software switching codes to enter. In fact, a PC is not even required. The subsequent data is transferred transparently; unlike software controlled switches where certain bit patterns can make the switches "burp" or even switch ports.

The KEYs are programmed from the 232-PSS (Also see Remote Programming), no PC is required. They may also be programmed selectively so that only certain KEYs allow access to certain ports, or to broadcast to all ports.

Since the 232-PSS initiates its operation on the analog side of the operative modems, the system is completely hardware and software independent. Once the automatic setup is completed, all of the asynchronous RS-232 signals are linked transparently between the modem and the DTE; except for "ring". No data rate setup is required on the 232-PSS and there is no buffering or band pass limitation. Outbound calls through the 232-PSS are also isolated and can be placed from any port transparently, or not allowed.

The 232-PSS was primarily designed for remote maintenance applications, but it can be used for any remotely controlled switching requirement or even used as a secure broadcast switch to multiple RS-232 devices, such as printers.

Maintenance ports are becoming a preferred path of entry for hackers. As the number of maintenance ports increase on commonly available hardware operating with well-documented mainstream operating systems, security is becoming an urgent issue.

The system is deceptively simple to use for the high degree of security and type of switching options that it provides.

REMOTE PROGRAMMING (Programmer Required)
The security code in the 232-PSS and corresponding Keys can be changed locally or remotely. This is accomplished automatically by simply connecting the optional random number Programmer to a telephone line and calling the 232-PSS. This provides a very quick and easy method of protecting multiple sites if a security Key is discovered missing. The Keys can then be programmed in a more leisurely manner by having the Keys call the Programmer or the Programmer call the Keys.

Also see the Modem Router Switch (MRS). It provides a similar function to the 232-PSS, except that the switched ports are analog modem ports and not RS-232 ports.


Security Selection Key Also Required

Item No SWT232-8    Price $325.00

Physical    7.5" W x 4.25" D x .75" H, 1 lb.
Connectors  (2) RJ-11 TelCo/Programming,
            (8) RJ-45 RS-232,
            (1) DB-9 Male RS-232
LEDs        (12) Power, Mode, Key Program
Switches    (1) Manual Rotary 8 Position, 
            (1) 4-Bit Dip, (1) Pushbutton
Bell        None
Cable       (1) 5' RJ-11 Phone Cable,
            (1) 6' DB-9 Female to DB-9 Male
Adaptor     None
AC Power    Wall Mount 9VAC 1A, 115V/60Hz

NOTE: For 220V/50Hz, add (-INT) to the Item No

Item No SECRS-8
Quantity     1-5     6-10    11-25   26-50 
Price each   $79.00  $74.00  $65.00  $55.00

Physical    1.5" W x 3" D x .75" H, .25 lbs.
Connectors  (2) RJ-11 TelCo
LEDs        (1) Verify Connection
Switches    (1) Manual 8 Position Rotary
Bell        None
Cable       (1) 15" RJ-11 Phone Cable
Adaptor     None
AC Power    None

RJ-45 to DB-25 Female RS-232
Item No CA5R45-F    Price $7.50

RJ-45 to DB-9 Female RS-232
Item No CA9R45-F    Price $7.50

Physical    2" W x 1.75" D x .5" H, .25 lbs.
Connectors  (1) RJ-45 RS-232,
            (1) DB-25 or DB-9
LEDs        None
Switches    None
Bell        None
Cable       None
Adaptor     None
AC Power    None

Item No PSS-232-P   Price $125.00 

Physical    1.5" W x 3" D x .75" H, .25 lbs.
Connectors  (2) RJ-11 TelCo
LEDs        (1) Programming
Switches    (1) 4-Bit Dip
Bell        None
Cable       (1) 15" RJ-11 Phone Cable
Adaptor     None
AC Power    None


Computer Peripheral Systems, Inc.
5096 Bristol Industrial Way, Suite B
Buford, GA 30518
8:30 AM - 5:30 PM EST
Technical Support
(770) 945-0643
8:30 AM - 5:30 PM EST
(770) 945-9342

© Copyright 1996-2003  Computer Peripheral Systems, Inc.
This file last modified August 29, 2003