Move to digital means money in this bank - Branch Banking and Trust Company moves to a digital network from an analog network using Racal-Datacom Omnimux 9000 T1

Communications News, Sept, 1993

If it ain't broke, don't fix it" is a popular axiom, but in the fast-paced world of data communications unwise adherence to that axiom can break the bank.

Dennis Breen, vice president of Branch Banking and Trust Company of Wilson, N.C., is in charge of his company's data communications network serving about 230 banks in North and South Carolina. Under Breen's direction, the bank made a significant transition to digital networking using Racal-Datacom systems and support services.

Several years ago he had a traditional computer network using telephone-focused analog technology, but he was hearing many industry people talk about converting such networks to computer-focused digital technology.

"I always said we would never move to digital unless the economics of such a move made sense - or we needed higher bandwidth that would force us to add digital circuits," Breen recalls. "Both happened."

Once Branch Bank & Trust determined that digital networking made economic sense, it converted its two-state data network to digital in one swift leap. The company has about 300 locations.

"The main reason we went to digital was because we saw the telcos encouraging large-scale computer users to move in that direction," Breen says. "Especially in North Carolina, the telcos had been urging customers toward digital for years."

Southern Bell, for example, introduced pricing which - combined with digital's superior transmission quality and service continuity capabilities - made such a move economically attractive to its business customers.

Breen had an analog network using a Racal-Datacom Omnimux 9000 T1 multiplexer as the backbone.

Branch began its network conversion from analog to digital at 9,600 b/s. This is a preface to changing its entire wide area network to an interconnected series of local area networks.

"We were able to convert our 4,800 b/s analog circuits to 56 kb/s digital circuits at almost no cost," Breen says. "That means we could do more things and provide customers with more services and have the network operate much faster. Circuit costs went up a little but maintenance and leasing costs of analog equipment went down.

"Also, we eliminated time-division multiplexers and some other network equipment associated with our analog backbone network."

The bank's new digital network uses the 9000 backbone to connect a pure digital network of Excalibur multiport/ multidrop products at each of the branch locations, providing transmission speed of up to 56 kb/s. Nodes are at Charlotte, Gastonia, Raleigh and Wilson, N.C.; and Columbia, S.C.

At the computer network's central site in Wilson, an Excalibur Single-Ended T1 (Set-1) DAP connects a feeder T1 to the backbone. This centralization of equipment saves money for the bank by reducing the need for trained network staff at remote sites while increasing the bank's control of the network.

The network is managed by the Communications Management Series (CMS) 400 Racal Management System.

Branch Bank circuits terminate in Southern Bell and Carolina Telephone areas that Southern Bell calls FlexServ nodes. Southern Bell provides multidrop bridging at the central office, consolidating all circuits within that LATA into a T1 facility feeding the T1 backbone.

Omnimux 9000 serves as a backup by providing automatic rerouting of circuits in the event of a backbone T1 circuit failure. The backbone also allows the rerouting of the network to the bank's disaster recovery facility in New Jersey.

Flexibility of the data network also is important. The bank made many acquisitions in recent years, and the network had to adapt to each sign of growth.

"Using the telephone CO (central offices) as a concentrator or bridge point and mapping the network at the CO into the T1 allows us to add a branch location in about four weeks, because we don't have any long-distance engineering to do," Breen says. "Everything is essentially a local loop. That's added quite a bit of flexibility. In most cases the way circuits are designed, we can just add a location to one of our multidrop circuits in a very short period of time by just mapping it on at the central office.

"With the new network, we can make changes within 30 business days that previously required 60 to 90 business days," Breen adds.

The many business functions of a bank mean a growing variety of applications use the computer network. These applications need higher bandwidth.

"We run many applications over this backbone network," Breen says. "We have a number of platforms using a branch's circuit. There's security, loan automation, automated teller machines, branch automation and point-of-sale teller activity."

Using the multiport/multidrop mode enables Branch Bank to create independent, multidrop virtual 9,600 b/s channels within the 56 kb/s bandwidth of the transmission facility. The port sharing capability allows two applications, such as security and automated teller machines, to share a single 9,600 b/s circuit.

"It was a tough job rolling it all out due to the extensive geography we had to cover. It's working well for us. We went to this as part of our migration strategy to go to local area networks. We will continue to move in that direction when we remap the bridges at the central offices to bring 56 kb/s circuits directly back to Wilson. The current network is designed to do that without re-engineering costs," Breen concludes.