Transmission Only Applications

Problem
You need permanent (nailed-up) analog connections for the level and pressure sensors in your brewery. A modem connection links the process and cooking computers to the control center. A good public address intercomintercom system dispatches operators to accomplish mixing, cooking, and flow control. The master brewer needs to keep an eye on the whole process from a central site.

Solution
Coastcom's 2-Wire and 4-Wire voice frequency cards support TO mode for analog alarm monitoring, permanent on-line modem connections, and intercom systems.

How Does It Work?
The TO connections allow a control center to extend its ears and voice to many locations.

Figure v20. TO Applications

What Actually Occurs?
TO mode allows permanent voice frequency connections to be made between locations. TO mode provides full duplex (transmit and receive) operation. It is referred to as transmission only mode because telephone signaling protocols are not used.

Coastcom's 2-Wire and 4-Wire channel cards offer TO modes of operation. The FXO is the preferred 2-Wire channel card since it does not supply talk battery; the FXS channel card supplies talk battery. If using an FXS card, talk battery would be applied to the ring lead possibly causing damage to your dedicated modem. All 4-Wire channel cards can be configured for TO operation.

Stuart is master brewer for the swing shift at the Green Town brewery when a sensor detects a quick pressure rise in one of the cooking vats. The pressure sensor sends an analog voltage level, over a 4-Wire TO circuit, to the control center.

At the control center Stuart requests the latest temperature and process information from the control computer of the vat with the high pressure; this is accomplished over a dedicated 2-Wire TO modem circuit. After analyzing the current temperature and process information Stuart decides a quick chemical analysis of the batch is required.

Kurt is the floor operator in the building where the high pressure vat is located. Stuart comes over the intercom system to locate Kurt and communicate the procedures for a test sample. Before Kurt can take a sample, a pressure alarm occurs. Stuart comes on the intercom again and directs Kurt to postpone the sample and open the overflow pressure valve.

How Do You Set It Up?
Intercom and sensor circuits are carried over the 4-Wire TO circuits. 2-Wire modems are set-up permanently over 2-Wire TO circuits. Select TO mode on any of the 4-Wire or 2-Wire cards.

What Do You Order?
For each intercom and sensor a 4-Wire TO circuit is required at the control center and brewing station. For each 2-Wire modem circuit a 2-Wire circuit is required at the control center and brewing station. You will also require two D/I Mux IIIs, one at the control center and one at the brewing station.

Voice Grade Data Application

Problem
You have a centralized distribution center which supplies all of your retail outlets. Purchasing, inventory control, and shipping are all located at the distribution center. The market changes rapidly and you want to automate inventory control so that a daily analysis can be done of each retail outlet's needs. Timely purchasing and distribution are required to keep up with the competition and buying trends.

Solution
4-Wire modem service can be centralized over a T1 transmission facility by using 4-Wire voice frequency channel cards in the Voice Grade Data (VGD) mode. Coastcom's Dual 4-Wire E&M channel cards (Part Numbers 33245-104 and 33245-123) offer VGD modem service.

How Does It Work?
Dedicated analog modems at the various retail outlets are always on line to the control center through the D/I Mux III and 4-Wire modem connections.

Figure v21. Voice Grade Data Applications

What Actually Occurs?
Voice Grade Data circuits are often used in applications where speed is of the essence. With VGD high speed 4-Wire modems can be accommodated without concerning yourself with data hits. This is an advantage over standard modem circuits, which often are used in TO applications

Your buyer, Angie has purchased two crates of "Beautiful Bears" stuffed animals and placed them on the shelves of your retail outlets. The manufacturer of "Beautiful Bears", George, says he will sell 10 more crates at a reduced rate if you can take delivery within 10 days.

The sales activity regarding the "Beautiful Bears" has been slow up to this point, however the latest "Beautiful Bears" children's movie has just been released in the theaters. Suddenly all the "Beautiful Bears" are sold at two of your retail outlets. Your inventory control contacts Angie through the high speed modems.

Angie acts quickly and contacts George immediately to accept the discounted shipment and to search for other "Beautiful Bears" spin-off products. Your timely purchase allows you to sell at a competitive rate and bring more customers into the retail outlets.

How Do You Set It Up?
Dedicated modem service is purchased at each of the retail outlets so that inventory information can be transmitted to the distribution center. At the distribution center a D/I Mux III with Voice Grade Data circuits also connect to permanent on-line modems and to the inventory control computer.

What Do You Order?
For each 4-Wire modem at the distribution center a Voice Grade Data circuit is required. Each 4-Wire channel card, either 33245-104 or 33245-123, supplies two circuits. A D/I Mux III is also required at the distribution center.