Remote Code Operated Access Switch

4 to 152 Port Code Activated Switch for RS-232 Asynchronous Device Access

Code Operated switch

  • 4 to 152 Ports, 2 or more control ports
  • Control ports may be RS-232, internal modem, internal Ethernet (TCP/IP)
  • Up to 38,400 bps port speeds (19,200 bps on master-slave units)
  • Plain English prompts, user definable
  • Name or port number switching
  • Control lead or code disconnect
  • Connect to any other async devices
  • Optional 12, 24, 48,120VDC, 240VAC power supply
  • Password protected
  • Dial-through alarm/paging capability
  • Industrial Temp operation, -40 to +75 C
  • V.90 internal modem available on most models





The DCB Access Switch is an ASCII character controlled switch used to connect one to six RS-232 async control devices to 4 to 152 async ports. Connection is made by entering the port number or port name. Disconnection is via entering a control code or lowering an RS-232 control lead. Either the port being controlled or the originating control port can lower a control lead to force a disconnect.

The DCB Access Switch can be used to access any async device from a terminal or PC. The Access Switch is especially suited for accessing RTUs, modems, DSUs, multiplexers and hubs locally or via modems from a remote location.

The Access Switch is available in 4, 8, 16, 24, 32 and the expandable AS-24M version. Units with 32 or less output ports have two input (controlling) ports; larger ones have 6. The AS-24M is a 24 channel master unit with six input ports and 24 output ports. The AS-24M can be expanded by attaching up to four AS-32S slave units. The AS-32S increases the Access Switch to 56 ports, 88 ports, 120 ports or 152 ports.

The Access Switches have a minimum of two input ports allowing both local control and remote dial-in access. All input ports can be active at the same time. The user accessing the switch always gets positive feedback. Before connect and after disconnect, the Access Switch gives the user an "Access >>" prompt. Port switching requires no cryptic code entry. Ports can be accessed by name or by port number.

If the devices being accessed can be forced to lower an RS-232 control lead on command, as is the case with most modems, DSUs and multiplexers, disconnection can be via the hardware disconnect method. This makes the switch 100% data transparent, suitable for use between devices transferring binary data. Data transparency also insures that no control codes inadvertently cause a disconnect. Using hardware disconnect, a dial-in modem can be used for remote computer support and for accessing the communications equipment (DCB modems, DSUs and muxes or radios).


The DCB Access Switch enables remote management of any RS-232 controlled device. Access Switches are commonly used to provide remote management on Cisco and Bay Network routers, HP and 3Com LAN hubs and switches, various brands of DSUs, UPS and T-1 channel banks, as well as remote access to minicomputers and UNIX servers. If using in-band network management (with or without SNMP), you can't get "into" the equipment at the most critical time when your network is down! By also using an Access Switch along with a dial-in modem, you are assured of a direct route to all remote equipment for troubleshooting and reconfiguration with only one modem phone line.

AC Power Control

The Access Switch mates with the APS-01 to control AC power to remote devices. Commands associated with power control are ON, OFF, and REBOOT. Remote equipment up to 10 amps at 120VAC can be controlled. The access switch provide positive feedback and the status of AC power can be displayed. The APS-01 has a "fail ON" feature to prevent server downtime in case of trouble. See the APS-01 data sheet for details.

Dial-through capability

The dial-through feature allows the Access Switch to be used with servers and other devices both for dial-in or local terminal connection for maintenance, and at the same time the servers can dial out with paging or alarm messages.

For example, the newest HP lan servers have a single port that functions as a local terminal or dial in port for maintenance, and the same port is used to dial out to paging systems when there are server system faults. Access Switch users who have HP servers and other devices (routers, 10/100 switches, DSUs, etc) connected to the Access Switch can now use the same dial in modem for getting to the server and paging out from the server. All that is required is to set up the Access Switch port that the HP server connects to as a DIALBACK port.

The DIALBACK option of the Access Switch allows an Access Switch port to be used both to access devices like the server and at the same time allow the server to go through the Access Switch to get to the modem on an input port and send out a page for emergency notification. The Access Switch senses the AT commands from the device on the Access Switch output port, opens up a path to the Access Switch modem and passes on the AT dialing commands sent from the device to the modem.

The new Access Switch firmware that includes the DIALBACK option also adds a set up string for modems connected to input port 1 of the Access Switch. This setup string is used to insure that modems connected to the Access Switch are "well behaved", and operate in a way that is controlled by the Access Switch. To insure proper modem operation, the setup string is sent to the modem when the Access Switch is powered on, when it is reset ,and at the end of a dial up call.

Internal TCP/IP Ethernet Interface

The internal ethernet TCP/IP option allows a direct ethernet connection. Control the Access Switch and connected equipment by telnet to the Access Switch. Use any telnet program, or pre-saved scripts from any ethernet workstation. This is option is available only on units with 8 or more ports.

Internal modem

The internal modem option is a built-in V.90 modem. Internal modem commands provide direct access to the modem, and provide a command string to be sent to the modem after every power on, after disconnect and at the end of every dialback paging session. The modem initialization command insures reliable modem operation.



AS-04 - 4 port model
AS-08 - 8 port model
AS-16 - 16 port model
AS-24 - 4 port model
AS-32 - 32 port model
AS-24M - 4 port master
AS-32S 3- 2 port slaves for AS-24M

Input Control Ports

AS-04, 08, 16, 24, 32 - 2 ports
AS-24M - 6 ports

Output (Controlled) Ports

AS-04 - 4 ports
AS-08 - 8 ports
AS-16 - 16 ports
AS-24 - 24 ports
AS-32 - 32 ports
AS-24M - 24 ports
AS-32S - 32 port expansion unit for AS-24M
Access Switch System Sizes: 4, 8, 16, 24, 32, 56, 88, 120, 156 ports

Port Specifications

Data Format:

1 Start bit
8 Data bits including parity if used
1 Stop bit
10 Bits total


Input Ports: Autobaud to 1200, 2400, 9600, 19,200, or 38,400 bps OR fixed at 1200, 2400, 4800, 9600, 19,200, or 38,400 bps asynchronous only.

Output Ports: on AS-04 through AS-32: Independently set for 1200, 2400, 4800, 9600, 19,200, 38,400 or “Follows Input Port”.

Output Ports: on AS-24M/32S: Matches input port rate up to 9600 bps. Rate conversion from 19,200 to 9600 is automatic.

Interface: CCITT V.24, RS-232D
Connectors: RJ-45 (8-wire)

Indicators (front panel)

AS-24M - "Master" LED
AS-32S - "Slave" LED, Port Range

Operational Commands

Help screen
Show Port ID
Port On
Enter Setup
Port Off
Set Parity
Port Cycle
Dial-throuch comands

Configuration Commands

Set Password
Set Port ID
Set Rate
Set Disconnect String
Set Prompt (Changes ACCESS>>)
Reset and Keep Memory (Exit Setup)
Reset and Clear Memory (Exit Setup)
Show Status
Show Port IDs
Show Connections
Modem Configuration Commands
Help Screen


Power requirements: 120 VAC, 30-43 watts, .25-.36 amps
12, 24, 48, 125 VDC and 240 VAC Power supplies optional

Temperature Specification: -40 to +75C

10 1/4" x 9 3/4" x 2 1/4" (AS-04, AS-08 and AS-16)
10 1/4" x 9 3/4" x 4 1/2" (AS-24, AS-24M and AS-32S)

Code Activated Switch

Rear view of DCB Code Operated Switch AS-04 (4 port)

Code Operated switch
Rear view of DCB Code Activated Switch AS-32 (32 port)



APS-01 AC Power Switch with the Access Switch

Applications Notes and Manual

Download the User Manual
Download a PDF version of this data sheet.
Download a PDF Overview Document
Short four page document describing some Access Switch applications

Remote Network Management Cuts Into Frequent Flyer Miles:
Prudential Securities Solidifies Nationwide Network Uptime
Customer success story about Prudential Securities using DCB Access Switches to lower cost and improve network uptime.
Network Management, SNMP vs. Out-of-Band Management.
The realities of managing your LAN/WAN with SNMP and how Out-of-Band management can make the system more effective.
Saving Time and Money... The DCB Access Switch and Remote Maintenance
Ways to save money and time by using the DCB Access Switch.


Available in 4, 8, 16, 24, 32 port units, and expandable Master/slave system sizes of 24,56,88,120, or 152 ports. All units may have two RR-232 control ports, each of which may be substituted with either an internal ethernet(TCP/IP) or an internal modem interface. Larger systems using the AS-24 master have 6 control ports.

AS-04 4 Access Ports, 2 Control Ports $1115
AS-08 8 Access Ports, 2 Control Ports $ 1,675
AS-16 16 Access Ports, 2 Control Ports $ 2,250
AS-24 24 Access Ports, 2 Control Ports $ 2,800
AS-32 32 Access Ports, 2 Control Ports $ 3,350
AS-16/V.32 16 Access Ports, 2 Control Ports, Internal V.90 Modem $ 2,575
AS-24/V.32 24 Access Ports, 2 Control Ports, Internal V.90 Modem $ 3,125
AS-32/V.32 32 Access Ports, 2 Control Ports, Internal V.90 Modem $ 3,675
AS-LAN Internal Ethernet TCP/IP Interface (not available for A-04 or AS-24M) $ 325
AS-24M 24 Access Ports, 6 Control Ports $ 3,350
AS-32S 32 Access Ports Expansion for AS-24M $ 3,350
APS-01 Remote Power Control Unit $ 220
PS-48 48 Volt Power Supply Option $ 75
PS-48 48 Volt Power Supply (Replacement) $ 125
Other Other Power Supplies Available Details Here $ See Datasheet Here
The Access Switche uses RJ-45 connectors. For your convenience when connecting equipment that uses 9-pin or 25-pin RS-232 connectors, order RJ-DE9 or RJ-DB-25 adapters at $12.00 each. Contact your sales representative for the proper part number to match your equipment.

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Dewey, Il 61840
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Toll Free: 800-4-DCB-NET
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Email: Contact Page
Fax: 217-897-8023
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