ECCI’s QuadRANT Remote Access System

Industrial-Strength Remote Access Hardware

Remote network access hasbecome a necessary component of most corporate networks. As the number oftraveling salespeople and telecommuters continues to grow, so do therequirements for remote access systems. Choosing software is easy: A Windows NTServer with Remote Access Service (RAS) can support up to 256 simultaneous usersand provides a stable, secure environment for dial-in clients. Choosing hardwareis not so simple. Most devices that provide access to multiple modems areavailable only in four-, eight-, or maybe 16-port versions, and you can quicklyoutgrow them.

Enter ECCI's QuadRANT remote access system. It includes several optionsthat can take you from a four-port ISA modem adapter to rack-mounted modem poolsthat will reach and exceed NT's limit of 256. Expandable is an understatement.

Have Some Port
ECCI's entry-level remote access product is the QuadRANT.ecm, a four-portplug-and-play ISA card (at least, as close as NT can get to plug-and-playthrough proprietary software) with four 28.8Kbits per second (Kbps) data/faxmodems. Just install the board (make sure you have a full-length slotavailable!), and turn on the system. After you log in, you install the software,and the ECCI setup program will search for and allocate an available interruptand I/O address.

A great feature of the QuadRANT.ecm is its expandability. You can use it asa control board for external modem cabinets to control up to 64 additionalmodems connected by the COMM bus (a simple 9-pin serial connection). ECCI hastwo cabinets available, one that holds from four to 24 modems and another thatholds four to 64 modems. ECCI's configuration software makes setting upadditional modems simple. After using the COMM bus to connect your QuadRANT.ecmand the external cabinet, start the QuadRANT Port Manager. Choose FullConfiguration from the Configuration menu, and your new COM ports will be readyto go.

At the high end of ECCI's spectrum is the QuadRANT COMRAK cabinet. TheCOMRAK is a rack-mountable cabinet that can hold any combination of up to 64modems or high-speed serial ports. Nearly everything in this cabinet ishot-swappable, including any of the three cooling fans, the three redundantpower supplies, and the QuadRANT modems. That's industrial strength.

From Server to Module
You can choose between two methods to connect the COMRAK cabinet to yourserver: with a differential SCSI controller or a QuadRANT.ecm board as acontroller. The COMRAK cabinet is rack-mountable, and because it will probablynot be within just a couple of feet of your server, the easiest method is with adifferential SCSI controller. This configuration will give you the bestperformance. We used an NCR-825 PCI card to connect to the ECCI. (DifferentialSCSI provides a separate ground line for each data line, and high-impedancetermination. Because this reduces line noise, you can use much longer cables forconnecting peripherals; the tradeoff is that you cannot use this bus forconnecting standard SCSI devices.) You can then chain several COMRAK cabinets onthe SCSI bus to reach NT Server's RAS limit of 256. The other method, with aQuadRANT.ecm board as a controller, uses the COMM bus to connect the COMRAK.This method requires the additional purchase of the QuadRANT.ecm board, and youcannot add more modems because of the QuadRANT.ecm's limit of 64 additionalmodems.

When you use SCSI to connect a COMRAK, the interface between thecommunications devices (either modems or serial ports) is a Control Module (CM).The two types of CMs are the Single Channel Control Module (SCCM) and the DualChannel Control Module (DCCM). The SCCM can control up to 64 lines. In contrast,with additional external cabinets connected using the COMM bus, the DCCM cancontrol up to 256 lines. The CM provides its own processor so you can offloadmost of the connection processing from your server. The DCCM we got with thetest system had an 80386SX processor.

At the heart of the QuadRANT system are Protocol Line Modules (PLMs). Thetypes of PLMs are the Asynchronous Stackable Quad-Processor adapter (ASQ-P), theAsynchronous Quad adapter (ASQ), and the Modem Asynchronous Networking adapter(MODAN). These modules comprise the system's communications ports.

The ASQ-P adapter provides four high-speed serial ports that can operate atspeeds ranging from 50bps to 150Kbps. The ASQ-P sports an AMD29000 RISCprocessor and can control from four to 24 serial ports. On the ASQ-P adapter arefour RJ-45 connectors that use RJ-45 to DB-25 cables to connect to standardserial devices. These adapters are ideal if you have a ready supply of externalmodems. The ASQ-P adapter is hot-pluggable. If you need to repair or replaceone, it doesn't affect the entire COMRAK cabinet. To swap out an adapter, yousimply remove the ASQ-P from the cabinet. RAS will show a hardware failure forthe four COM ports belonging to that adapter. When you install the new adapter,the ECCI software will reconfigure the ports, and RAS will show the ports asready to roll.

If you need additional serial ports but don't want the expense of everyadapter having its own processor, you can get the ASQ adapter. It is a daughtercard that connects to the ASQ-P and uses the ASQ-P's processor and memory. EachASQ adapter has four RJ-45 ports, and you can chain five daughter cards to anASQ-P, for a total of 24 serial ports. The disadvantage to chaining the adaptersis that if you need to hot-swap, you cannot remove just the inoperable card; youmust take the whole batch. If you attach five daughter cards to a processorcard, you must remove all 24 ports while you replace the malfunctioning card.

If you don't already have all your modems, you can consider the MODAN. Italso provides four ports on the adapter, but it includes four integrated modems.MODAN cards are available with either 14.4Kbps or 28.8Kbps modems. Each MODANadapter also has an AMD29000 RISC processor on board. Each modem has an RJ-11connector, a set of indicator lights, and an individual reset switch. And, likethe ASQ adapters, the MODAN adapters are hot-pluggable. If a card fails while auser is connected, you just install a new card, and the software will doeverything but reconnect the user.

A final available component that I did not get for review is the CoaxInterface Line Module. It lets you use coaxial cable to extend the external COMMbus up to 1000 meters. If you need cabinets in several locations but want justone server, you can buy a DCCM control module and use coax to chain additionalcabinets.

Installation and Setup
Setting up the ECCI was easy once we knew the proper procedure. The onehurdle in the installation process comes up if you don't already have RASinstalled when you set up the ECCI. When we installed the ECCI software, itasked whether we wanted to add the ECCI modem response strings to the modem.inffile. Without these strings, Windows NT will not recognize the modems. Weresponded with a yes, and finished the installation process. When we theninstalled RAS, it installed a fresh copy of the modem.inf file, overwriting thestrings we had just added. When RAS tried to detect a modem, it could notrecognize one.

Unfortunately, RAS will not install until a COM port has been configuredwith a modem. So, in a vicious circle, RAS will not install until it can detecta modem; it cannot detect a modem until the modem.inf file is changed, and youcan't change the modem.inf file until RAS is installed; otherwise, RAS willoverwrite the file.

We were finally able to install RAS by manually telling Setup that themodem was a generic Hayes-compatible modem. Then we changed the modem.inf fileand changed the configured port to the proper modem type.

You will have this problem any time you attempt to set up RAS for the firsttime using an unsupported modem. Perhaps future versions of Windows NT will letyou set up RAS without having to specifically configure a modem.

One nice feature of the ECCI system is that, whether you have four ports or256, each is set up as an individual COM port. This way, any software that cancommunicate with COM ports can talk to any port on your ECCI system. And if youuse port sharing software, such as SpartaCom's Asynchronous Port Sharingpackage, you can make every port available across the network for dial-out.

Price Is No Object
You pay a price for the comfort and convenience of having 64 modems tuckedinto a tiny box, with hot-swappable fans, power supplies, and modems. The costof our test system, with the COMRAK cabinet, a SCSI control module, eightasynchronous ports (one ASQ-P and one ASQ), 40 14.4Kbps modems, and 16 28.8Kbpsmodems, comes to just more than $28,000. ECCI has prices for variousconfigurations, with both SCSI- and ECM-based prices, as you can see in table 1.These prices are for 28.8Kbps modems, the most popular configuration. Suchprices aren't for everyone, but if you need a highly reliable, expandable,easy-to-set-up remote access system, consider the ECCI QuadRANT system.