SR Statistical Multiplexer

Statistical Multiplexer, 1 to 32 channel for Leased, Radio, Satellite, and Dial-up Lines

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8/16/24/32 Port Model SR-08,
SR-16, SR-24, SR-32
4 Port Model SR-04

Port Specifications
Network Specifications
Operating Modes
Indicators (front panel)
Network Management Port
Network Management Port Commands
How to Order
Download the 1 and 4 Port Manual
Download the 8-32 Port Manual


  • Individually configured asynchronous ports
  • Port speeds to 38.4 Kbps, (Up to 57.6 Kbps with SR-04)
  • Synchronous composite to 128 Kbps, async to 115.2 Kbps
  • Network Management Port
  • Remote set up and testing
  • Leased line, dial up, or any serial composite
  • "One Touch Dial" for modems and satellite terminals
  • 1, 4, 8, 16, 24 or 32 channel models
  • Test message generation
  • "Data Scope" functions to allow monitoring of any data port
  • Composite link is error corrected
  • Field upgradable
  • Optional internal 56 Kbps DSU/CSU
  • Optional internal V.90 modem


The SR series statistical multiplexers concentrate 1,4, 8, 16, 24 or 32 asynchronous channels over a synchronous or asynchronous composite. "One Touch Dial" mode is included for satellite modems or dial-up modem links. With "One Touch", the SR uses a dial-up modem. At the touch of a single key (space bar or enter key), any terminal connected to the SR multiplexer initiates a call. The SR is on line in just a few seconds. If the link is idle for a user settable time ranging from 1 minute to 99 minutes, the SR automatically disconnects the connection, saving costs where charges are time metered.

All port parameters are set with an asynchronous terminal (or PC) connected to the network management port or port 1. Set-up procedures are menu driven and fully explained on screen. All configuration parameters are maintained through power outages.

The asynchronous ports can be individually set for speeds to 38.4 Kbps (57.6 Kbps on the SR-01 and SR-04). Hardware (CTS/Busy high or low) or software (Xon/Xoff even, odd, mark, space or transparent) flow control is also set on a port by port basis. Flow control is transmitted across the link.

The SR multiplexer composite is synchronous or asynchronous full duplex lines either analog or digital. The composite can be run at speeds up to 128 Kbps sync, 115.2 Kbps async.

The network management port includes local and remote configuration commands. The Show Configuration Commands allow the system manager to view the configuration settings of both the local and remote SR Multiplexers. Network management features include port and composite loopbacks, capture of a remote or local port, send a test message to an individual local or remote port, set multiplexer ID for node identification and a built-in "data line monitor" which allows the monitoring of the transmit or receive lines at the local multiplexer. A unique feature of the SR multiplexers is the Copy Command. This command allows a trainer at the host site to "copy" any local or remote port to view exactly what the user is entering. This feature can save thousands of training dollars by eliminating travel expenses.

The SR multiplexer has a side panel access for firmware cartridge installation. This feature simplifies installation of upgrades for new features and functions.

The SR multiplexers are compatible with all async protocols for machine-to-machine or host computer-to-remote links. It transfers all binary characters transparently. In addition, with features like the loopback, test message, ID, monitor and copy commands, you can take charge of your network like never before.

The single port SR multiplexer is quite useful for multi-drop and multi-point applications such as point-of-sale terminals, SCADA, and other machine control applications or where it is desireable to transfer RS-232 control leads across a data connection that doesn't transport transport them natively.
The internal modem is available in a V.90 version. With the internal modem, multiplexer management commands provide direct access to the modem, and provide a command string to be sent to the modem after every power on. These units can also be configured for the "one-touch" operation, whereby a link is dialed up by simply touching the space bar on ANY terminal connected to the multiplexer. The modem initialization command insures reliable modem operation. Using the internal modem removes many of the dial-up problems cause by unknown bargin-store quality modems.

Asynchronous Statistical Multiplexing
1, 4, 8, 16, 24 or 32 channels
All ports can be 38,400 bps
Port Specifications
Data Format
1 Start bit
8 Data bits including parity if used
1 Stop bit
10 Bits total
Rates: 300, 1200, 1800, 2400, 4800, 9600, 19200, 38400, (57600 on the SR-04) bps individually selectable per port
Interface: CCITT V.24, RS-232-D
Connectors: RJ-45 (8-wire)
Buffering: 64K dynamically allocated
Port Flow Control: Set on an individual port basis
Clear to Send
Busy High
Busy Low
Network Specifications
Rates: Follows modem clock signals to 128 Kbps synchronous, 115.2 Kbps asynchronous
Interface: CCITT V.24, RS-232-D
Connector: RJ-45 (8-wire)
Error Correction: Automatic retransmission
Network to modem/DSU cable included
Operating Modes
Normal on-line multiplexing
"One Touch Dial" mode
Network loopback
Indicators (front panel)
Power, Multiplexing, Receive Error, Modem Ready, Option, Port 1 Setup, Loopback
Network Management Port
Interface: CCITT V.24, RS-232-D
Connector: RJ-45 (8-wire)
Can be mapped to Port 1
Network Management Port to terminal cable included
Network Management Port Commands
Help Screen
Remote Test Loop
Monitor Transmit
Monitor Receive
Network Loopback
Flow Control Active
Set Time

Show Configuration
Show Network
Configure Ports
Configure Network
Port Loopback
Device Type
Capture Port
Copy Port
Send Test Message
Activity Counters
Power requirements: 120 VAC, 30-43 Watts, .25-.36 Amps (Optional 12, 24, or 48 Vdc Power supplies available)
101/4" x 93/4" x 21/4" (1,4,8, or 16 channels)
101/4" x 93/4" x 41/2" (24 or 32 channels)
Temperature: Operating Temperature: -40 to +75C

Rear view of 16 channel DCB SR Multiplexer


How to Order


SR-04 4 Port Host or Remote Multiplexer $ 775
SR-01 1 Port Asynchronous Multiplexer $ 500
SR-01/DSU 1 Port Asynchronous Multiplexer with built-in 56Kbps DSU $ 825
SR-08 8 Port Host or Remote Multiplexer $ 1,350
SR-16 16 Port Host or Remote Multiplexer $ 2,100
SR-24 24 Port Host or Remote Multiplexer $ 3,000
SR-32 32 Port Host or Remote Multiplexer $ 3,800
SR-V92 V.92 Internal Modem $ 325
SR-08-EC 8 Port expansion kit $ 1,300
SR-FR Frame Relay firmware
(Free when ordered with unit)
$ 500
SR-DSU04 Integral 56/64Kbps DSU/CSU for SR-04 $ 325
RK-8/16 Rack mount for 8/16 port unit $ 60
RK-24/32 Rack mount for 24/32 port unit $ 75
Above Prices include Point-to-Point or Frame Relay firmware.
See DCB Rack Mount Data Sheet for high density rack mounting options.
See Industrial DC Power Supply Data Sheet for 12, 24,and 48Vdc input power supply options.
There are many applications notes available from this web site. Click here!

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