Serial Code Operated Switch 2-Port


The Code Operated Switch (COS) is an asynchronous RS-232C and/or RS-422 switch. The COS can be configured RS232 on all ports, RS422 on all ports, or a combination of RS232 and RS422. These units are configured at the factory as requested at the time an order is placed, and it is recommended that the user examine the original purchasing documents to verify the configuration of the unit received.

Under code control, the master port can select subordinate ports. The master device (CPU/Terminal) selects any of the other ports (Printers/modems/terminals) by transmitting the proper arming and switching code. A communications link to the master port can also be made by any of the subordinate devices by transmitting its own channel address code while the switch is in the Switch Time mode. Once the communications link is established, all other ports are locked out. The ports remain locked out until either the master port or the selected subordinate port sends an arming character. Reception of the arming character causes the COS to
break all switched connections between the master and subordinate port and puts the unit back in Switch Time mode. The next character received by the COS is the “channel select character.” (See section 3.2) All ports have DB25S (female) connectors. Configuration switches on all ports allow configuration to a DTE or DCE port. The device also has switches to select baud
rate and word format (parity, character length, and number of stop bits). Figure 1-1 shows a network involving various peripherals. The computer selects which device it wishes to communicate with by transmitting the proper arming and switching code (0 through 3 for COS/4, 0 through 7 for COS/8). If desired, the connection can be made from a terminal (if these devices know the proper codes).
A 16 port device is also available, contact your sales source.

The COS/4 and COS/8 will also work in applications where the arming character can appear in the data stream (such as graphics, and error checking). When in graphics mode, an idle time (switch selectable) after the data stream is required before the arming character is valid. If an arming character is in the data stream, it will pass without causing the COS to switch.


Power:115/230 VAC (Switch Selectable), 60Hz, 11 watts

Size: 12.25” x 11.75” x 2.5”

Weight: 5.5 Pounds

Enclosure: Aluminum rack mount, plastic standalone

Interface: RS232/V.24, Full duplex, Asynchronous and/or
RS422/V.11, Full Duplex, Asynchronous

Controls:External – Vertical Switch (mode switch), push button reset
Internal – Baud rate (75,300-19.2K Bps) and format switch selectable
DTE/DCE configuration switch for each port
Auto Timeout (2.5 min., 5.0 min., 10 min. or infinite) switch selectable
Arming Character, switch selectable

Indicators: LOCKOUT and SWITCH TIME LED indicators. Segment display for CHANNEL SELECTED

Addressing: Two Digit code as follows:
First digit is switch selectable, initiates switch time – factory setting
is EOT(CTRL D), (Hex 04), (Decimal 04).

Second digit assigns channel, Hex 30-37 selects port 0-7.

Any channel can switch the channel when unit is in Switched Time
(unless disabled by SW6 positions 1-4).

The arming and switching code is stripped by the Code Operated
Switch. The arming character can pass as data in Graphics mode.

Data Rate: 300, 1200, 2400, 4800, 9600, 19.2K, 38.4K, 76.8K Bps

Humidity : 15% to 95% noncondensing

Temperature: Operating:- +32°F to 122°F (0°C to 50°C)
Storage: – 40°F to 158°F (-20°C to 70°C)



DCE Relcomm SCOS-2-115
DCE Relcomm SCOS-2-12
DCE Relcomm SCOS-2-48
DCE Relcomm SCOS-2-230