- RS-232 Port Sharing Device
- Interface – EIA RS-232, CCITT V.24, DB-25 Female Connectors
- Data Rates – Synchronous or Asynchronous to 128Kbps
- Anti-Streaming – Automatic or Manual for unattended Circuit Restoral
- DCE/DTE Selectable
- Tail Circuit Buffer
- Supports CSU/DSU’s, LL Modems, Dial Modems and Terminals
- RTS/CTS delays options
- Transparent to Data
- Fully Cascadable
- Internal or External Clocking
- Sturdy Metal Rackmount Enclosure
- -36 to -72 DC Input
DMM-4DC, DC Powered Port Port Sharing Device
DMM-4DC, DC Powered Port Port Sharing Device ,The RS-232 Digital Mixing Module (DMM-4DC) or port sharing device is a network expansion device for modem sharing or port sharing applications in polled or contention environments. The DMM-4DC allows up to four devices to share a modem /DSU or computer port. The port contention modes are RTS, DCD or switch on Data. Any combination of terminals and modems may be used in a network environment. Each port of the DMM-4DC may be selected as a DCE or DTE interface. Once installed, system and network efficiency are increased through higher host processor utilisation coupled with the significant decrease in idle time between host / terminal traffic sessions.
Ideal for either synchronous or asynchronous network environments, the DMM-4DC is protocol transparent at data rates up to 128Kbps. The DMM-4DC may be configured to provide clocking for the entire network. To prevent data transmission errors caused by clock differentials throughout a synchronous network, a 8 bit ring buffer is provided for re-synchronisation. In applications where the master port and the selected port provide their own clocks, data is clocked into the buffer at the receive clock rate of the active port and clocked out using the master port transmit clock.
In applications where the Clear To Send (CTS) control signal is not provided by the master port, an option for forced CTS is available via 3-position stick headers. Additionally, several user defined RTS/CTS delay settings are available.
The DMM-4DC also provides optional Anti-Streaming circuitry. Once enabled, Anti-Streaming will automatically remove a defective terminal or modem from service if the Data / Control criteria is present for the user predefined selection period.
The DMM-4DC is housed in a sturdy aluminium standalone or rack mount enclosure The unit is equipped with an internal -48 VDC power supply and will provide in excess of 315,419 hours of reliable service. All RS-232 data ports and the power supply have surge protection that utilise Sidactors.
The DMM-4DC has a three year warranty and a 24 hour turnaround on warranty repairs from the factory.
| Application | Multiple Sync/Async DCE/DTE devices operating in a polled, contention, or dial environment, to share one DCE/DTE port |
| Capacity | One to Four RS-232 Sync/Async devices |
| Interface | EIA RS-232 CCITT V.24 using DB-25 female connector |
| Data Interface on Delay Ports | Ethernet 10/100/1000 Copper |
| Data Format | Data transparent at all rates |
| Data Rates | Internal: Up to 76.8Kbps
External: Up to 128Kbps |
| Timing | Internal or External |
| Anti Streaming | Automatic…Selectable timeout intervals
Disable…….Selectable via DIP Switch |
| Terminal Service Moeds | Sequential scannong for RTS, DCD or Data |
| Front Panel | Indicators….Power, Transmit Data, Receive data, Channel Active, Channel Stream
Switches…..Enable/Disale of each Subchannel |
| Power Source | 100-120 to 200-220VAC@10%, 50-60Hz, 0.16/0.08A, external
110/220 volt select switch, IEC Power inlet, (2) 5mm Fuses |
| Regulatory Approvals Tested According to | UL 60950-1:2003, CAN/CSA-C22.2 No. 60950-1;2003
FCC Part 15, Class A |
| Environmental | Operating Temperature . .32º to 122º F (0º to 50º C)Relative Humidity.. . . . . . .5 to 95% Non-Condensing
Altitude. . . . . . . . . . . . . … .0 to 10,000 feet |
| Dimensions
DMM-4 (Rackmount Model) |
Height ……. 1.75 inches (4.44 cm)Width …….. 17.00 inches (43.18 cm)
Depth ……. 9.00 inches (22.86 cm) |
| Weight | 4.5 pounds (2.1Kg) |
| Warranty | Three years, Return to Base |
| Ordering Information | Model: DMM-4 Description: RS-232 four port Digital Mixing Module |
| Included with each unit: | 1) Operations Manual 2) U.S.A. Grounded Power Cord, Part # 713015 3) Optional Power Cords A) United Kingdom, Part # 713016 B) Continental Europe, Part # 713017 C) Other: Specify Country on Purchase Order |
| Optional Accessories | 1) Spare Data Centre Fuses
A) 160ma Fuse, Qty (2) Part # 714000 B) 80ma Fuse, Qty (2) Part # 714001 |