DMM-X21 Digital Mixing Module ITU X.21

Features/Benefits

• Interface - X.21, ITU V.11, (5) DB-15 Female Connectors
• Data Rates - Synchronous up to 1.024Mbps
• Anti-Streaming - Automatic or Manual for unattended Circuit Restoral
• Individual Subchannel Enable/ Disable Switches
• Integral Elastic Tail Circuit Buffer - FIFO capable of 512 bits per channel
• Up to Four DTE or DCE's per Link
• Transparent to Data
• Supports Fall Back Clocking
• Sturdy Metal Enclosure
• 110/220VAC Switch Selectable
• UL 1950 and CE Approved

The Digital Mixing Module X.21 (DMM-X21) provides the network manager with a cost effective means of expanding existing, leased line polled networks without adding computer ports or communications links. With the DMM-X21, up to 4 DTE or DCE devices can share the same port and communications link using the contention and control protocols normally resident in the host hardware and software.

Once installed, system and network efficiency are increased through higher host processor utilization coupled with the significant decrease in idle time between host / terminal traffic sessions.

Ideal for synchronous network environments, the DMM-X21 is protocol transparent at data rates up to 1.024Mbps. Data arriving at the Master Port is continually broadcast to all Subchannels. The attached terminal device that raises the Control (C) or Indicate (I) signal is automatically given control of the DMM-X21 until data transmission is complete. Clocking is accomplished from the attached Digital Modem.

The DMM-X21 incorporates optional Anti-Streaming circuitry. If enabled, Anti-Streaming will automatically remove a defective terminal from service if the Control (C) or Indicate (I) signal is present longer than the user predefined selection period.

Elastic Tail Circuit Buffers compensate for systems having different clock sources. Large 512 bit buffers enable the DMM-X21 as an ideal choice for VSAT or land line applications.

The DMM-X21 is equipped with an internal 110/220VAC switch selectable linear power supply and has a three year warranty.

Click here to view the DMM-X21 printed circuit board.

Specifications Application Multiple X.21 Synchronous DCE or DTE devices contending in a polled environment, to share one Digital DCE or DTE interface Capacity One to Four CCITT X.21 devices Interface CCITT X.21, V.11 using DB-15 female connectors Data Rates Up to 1.024Mbps Data Format Data transparent at all data rates Timing From Composite (Master) Port,Sub-channel Port 1 or Port 4 Buffers Up to 512 bits per channel  Anti-Streaming Automatic.....Selectable time out intervals Disable.........Selectable via dip switch  Front Panel Indicators....Power, Send/Receive Data, Channel Active, Channel Stream Switches.....Enable/Disable of each Subchannel Power Source 100-120 to 200-220VAC @10%, 50/60Hz, 0.32/0.16A, external 110/220 volt select switch, IEC Power Inlet, (2) 5mm Fuses 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 Height ....... 1.75 inches (4.44 cm) Width ........ 17.00 inches (43.18 cm) Length ....... 9.00 inches (22.86 cm) Weight 4.5 pounds (2.1Kg) Warranty Three Years, Return to Factory  Approvals  UL 1950, CE Approval, FCC Class A Ordering Information: Model: DMM-X21 Description: 4 Port Digital Sharing Device Included with each unit: 1) Operations Manual 2) U.S.A. Grounded Power Cord, Part # 713015 Options 1) Optional Power Cords ....A) United Kingdom, Part # 713016 ....B) Continental Europe, Part # 713017 ....C) Other: Specify Country on Purchase Order OPTIONAL ACCESSORIES 2) Spare Data Center Fuses ....A) 160ma Fuse, Qty (2) Part # 714000 ....B) 80ma Fuse, Qty (2) Part # 714001