PPP-SR-DSU Simple Router

PPP DSU - 56/64 K DSU/CSU with Sync to Async PPP Conversion

  • 56 and 64 Kbps DSU
  • 1 or 4 async 57,600 bps RS-232 ports
  • Converts sync PPP protocol to async PPP
  • "AT" command spoofing for Microsoft Windows95 and similar dialers
  • Use over DDS or DDS/frame relay
  • Ideal for Internet or intranets
  • Cost effective versus router + NIC + DSU
  • Reliable, high speed private line service alternative to dial up modems


Indicators (front panel)
Data Port





The DCB PPP-SR-DSU replaces a DSU, router and Ethernet network interface card (NIC) at remote locations for one to four PC's connecting to a corporate network or Internet service provider. The PPP-SR-DSU allows computers using async dial PPP programs (Windows95 Dial Up Networking, Chameleon, Spry etc.) to connect on a permanent private line link.

The DCB PPP-SR-DSU is a 56/64 Kbps synchronous DSU/CSU with one or four asynchronous ports and synchronous PPP or frame relay translation. The PPP-SR-DSU translates the synchronous protocols from the host router to asynchronous PPP and passes that to the async com ports of the remote PC's.

The unit is also available without the internal DSU, designated as the PPP-SR-01 one port unit and the PPP-SR-04 four port unit. Without the internal DSU, the PPP-SR can be connected to ISDN terminal adapters or fractional T1 channels at speeds up to 128 Kbps.
The PPP-SR-DSU negotiates the link with the computer and router as follows:

The PPP-SR-DSU is easy to install and operate. Controls on the unit include the loopback push button, a switch to select line driver or phone company clock and a separate management/setup port. The Setup switch is used to access the management port from the user's PC port. The minimum number of controls and comprehensive indicators make installation and troubleshooting easy. Diagnostic aids built into the PPP-SR-DSU include LED indicators and loopback capabilities.

The hardware cost savings provide a compelling reason to use the PPP-SR-DSU. It is especially cost effective where a number of PPP synchronous digital channels are delivered to the phone company via DS-0's and T1 access multiplexing, or via frame relay. The PPP-SR-DSU is a very cost effective alternative to ISDN. In many areas, phone companies charge ISDN users per minute usage rates. At the end of month, ISDN charges for even 8am to 5pm operation weekdays can total hundreds of dollars. A dedicated link using the PPP-SR-DSU is often the more cost effective alternative.



Rates: 56/64 Kbps synchronous (64 Kbps DSU to ship 9/97)
Async port rates to 57,600 bps
Application: Point-to-point
Facility: 56/64 Kbps Dataphone Digital Service (DDS) or equivalent, Line driver mode for customer owned 4-wire circuit. Supports frame relay at 56/64 Kbps

Indicators (front panel)

Power, Activity, Line Error, Modem Ready, Port 1 Setup, Loopback
DSU Led's: TxD, RxD, RTS, CTS, DCD, Test


Front panel push button for loopback
Side door accessible firmware cartridge for installing firmware upgrades
Rear panel switches for master or slave clock, RTS forced on or DTE controlled
Responds to telco current reversal loopback and non-latching pattern loopback.
Setup via the "Port One Setup" or via the rear panel setup port


Interface: DDS bipolar return to zero
Connector: 8-wire RJ-48S

Data Port

Interface: RS-232, V.24, speeds up to 57,600 bps
Connector: RJ-45 per EIA/TIA 561 pin outs


Power requirements: 120 VAC,
60 Hz, 18 Watts
10 1/4" x 9 3/4" x 2 1/4"
One pound

Rear view of DCB PPP-SR01-DSU


How to Order

PPP-SR01-DSU PPP-SR01 with internal DSU$695
PPP-SR01Sync to Async PPP Translator, uses external DSU, ISDN Terminal Adapter or channel bank port$595
PPP-SR04-DSUPPP-SR04 with internal DSU $895
PPP-SR04Sync to Async PPP Translator, uses external DSU, ISDN Terminal Adapter or channel bank port$795

Data Comm for Business Inc.
2949 County Road 1000 E
Dewey, Il 61840
Voice: 217-897-6600
Toll Free: 800-4-DCB-NET
Toll Free: 800-432-2638
Email: Contact Page
Web: www.dcbnet.com
Fax: 217-897-8023
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