DCB Remote Access

DCB Remote Access


4 to 152 Port Access Switch for RS-232 Async Device Access

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.

AS-04 Access Switch, 2 control Ports, 4 Device Ports
AS-08 Access Switch, 2 control Ports, 8 Device Ports
AS-16 Access Switch, 2 control Ports, 16 Device Ports
AS-24 Access Switch, 2 control Ports, 24 Device Ports
AS-32 Access Switch, 2 control Ports, 32 Device Ports
AS-24M Access Switch Master, 6 control Ports, 24 Device Ports
AS-32S Access Switch, 32 Ports Expansion for AS-24M
AS-08AOB 8 Port Add on Board
/V.92 Add for Internal V.90 Modem
/LAN Add for TCP/IP Port
/12, 24 or 48 Add for 12, 24, 48 VDC power option
/125DC Add for 125VDC power option

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.

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.

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.

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.

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.