TLS-1200
User’s Guide
7432 Alban Station Blvd., Suite A-105
Springfield, Virginia 22150-2321
(703) 912-4991
Table of Contents
Note
Description
Type of Service
Telephone Company Procedures
If Problems Arise
Installation
Operation
Block Diagram
Sample Cable for Connecting a TLS-1200 to an IBM-style personal
computer
Specifications
Written by Andrew Coile and Steve Stallings.
Revision 1.12
December, 1994
Copyright © 1992, 1994 by Practical Micro Design, Inc.
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publisher.
This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instruction manual, may cause harmful interference to radio communications. Operation of this equipment in a residential area is likely to cause harmful interference in which case the user will be required to correct the interference at his own expense.
The TLS-1200 is an interface unit that allows devices, which normally access a host modem via dial-up telephone circuits, to connect to local host equipment having an RS-232 port. The devices used with the TLS-1200 must contain a Bell 212A compatible 1200 baud modem, or a Bell 103 compatible 300 baud modem. A typical application would be connecting credit card verification devices to a private data transmission system or a local host computer.
When the TLS-1200 is installed, the telephone line originally connected to the user’s device can optionally be connected to a back-up line jack on the TLS-1200. The TLS-1200 then emulates the telephone line to the user’s device. If the host equipment should indicate a "not ready" condition, the user’s device is temporarily switched to the back-up telephone line.
The TLS-1200 is designed to be used on standard device telephone lines. It connects to the telephone line by means of a standard jack called the USOC RJ-11C (or USOC RJ45S). Connection to the telephone company provided coin service (CO implemented systems) is prohibited. Connection to party line service is subject to state tariffs.
The goal of the telephone company is to provide you with the best service it can. In order to do this, it may occasionally be necessary for them to make changes in their equipment, operations or procedures. If these changes affect your service or the operation of your equipment, the telephone company will give you written notice to allow you to make any changes necessary to maintain uninterrupted services.
If you have any questions about your telephone line, such as how many pieces of equipment you can connect to it, the telephone company will provide this information upon request.
In certain circumstances, it may be necessary for the telephone company to request information from you concerning the equipment that you have connected to your telephone.
Upon request by the telephone company, provide the FCC registration number and the ringer equivalence number (REN) of the equipment that is connected to your line; both of these items are listed on the equipment label. The sum of all of the RENs on your telephone lines should be less than five in order to assure proper service from the telephone company. In some cases, a sum of five may not be usable on a given line.
If any of your telephone equipment is not operating properly, you should immediately remove it from your telephone line because it may cause harm to the telephone network. If the telephone company notes a problem, they may temporarily discontinue service. When practical, they will notify you in advance of this disconnection. If advance notice is not feasible, you will be notified as soon as possible. When you are notified, you will be given the opportunity to correct the problem and informed of your right to file a complaint with the FCC.
In the event repairs are ever needed on the TLS-1200, they should be performed by Practical Micro Design, Inc. or an authorized representative of Practical Micro Design, Inc. For information, contact: Practical Micro Design, Inc., 7432 Alban Station Blvd., Suite A-105, Springfield, VA 22150-2321, or call (703) 912-4991.
The TLS-1200 should be located near the equipment with the RS-232 port to which it will be connected. Long wires connecting the TLS-1200 to the telephone lines are acceptable, whereas the cable carrying the RS-232 data should be as short as practical.
Make sure the telephone cables, RS-232 cable, and the cord to the power-pack will reach their intended destinations without stress.
Position the TLS-1200 so the ON-LINE light is visible, if desired.
The unit should only be exposed to the environmental conditions typically maintained for computer equipment, i.e. temperature of 40°F to 85°F, and humidity of 10% to 90% (non-condensing).
There are four connectors on the rear of the TLS-1200. The left RJ11 jack is marked "LINE". A cable connecting the TLS-1200 to the optional back-up phone line may go to this jack.
The right RJ11 jack is marked "EQUIP." A cable connected to the user’s device should be plugged into this jack.
The round connector marked "POWER" should be connected to the supplied 12 VAC power-pack.
The RS-232 port is a male 9-pin sub miniature D-series connector. Its connections mimic those used by serial ports on AT-style personal computers, and are as follows:
Signal |
TLS DB-9 |
Direction |
Description |
TXD |
3 |
To External |
Serial data transmitted from TLS-1200. |
RXD |
2 |
To TLS |
Serial data received to TLS-1200. |
DTR |
4 |
To External |
Active when off-hook, not switched to backup, and carrier present. |
DSR |
6 |
To TLS |
Active when external equipment active; Inactive causes equipment to switch to backup phone line. |
RTS |
7 |
To External |
Active when carrier is present at 1200 baud; inactive if 300 baud or no carrier present. |
CTS |
8 |
To TLS |
Ignored in Version 1.12. |
GND |
5 |
Common |
Ground |
The front of the basic TLS-1200 has one light marked "ON-LINE." This is illuminated only if:
When this light is off, the device plugged into the "EQUIP" jack is connected to the backup phone line which is plugged into the "LINE" jack.
If the TLS-1200 is "ON-LINE" (the DSR signal is active) and the external equipment goes off-hook, the following will happen:
1. The TLS-1200 will generate a simulated dial-tone for 100mS.
2. The TLS-1200 will generate a modem answer carrier.
3. The TLS-1200 will wait for an originate carrier from the external equipment, and will synchronize with the modem in the user’s device.
4. The TLS-1200 will assert RTS if the connection is at 1200 baud. If the connection is at 300 baud, RTS is not asserted.
5. The TLS-1200 will assert the DTR signal to indicate to the host equipment that a modem connection has been established.
6. The host equipment and the user’s device will exchange data as required. The TLS-1200 does not interact with this data transfer. The data rate will be either 300 or 1200 baud, as determined by the modem in the user’s equipment. The TLS-1200 does not buffer or speed-convert the data.
7. The connection continues until the user’s device goes on-hook, the modem carrier is dropped, or the host equipment de-asserts DSR. DSR is not required to cycle; it may be asserted continuously while the host equipment is ready.
Note that if the host equipment has the DSR signal inactive (so the TLS-1200 is not "ON-LINE") and the external equipment goes off-hook, the external equipment will be connected to the circuit plugged into the "LINE" jack on the TLS-1200.
Sample Cable for Connecting a TLS-1200 to an IBM-style personal computer
Signal |
Direction |
TLS DB-9 |
PC |
PC |
TXD |
To External |
3 |
2 |
3 |
RXD |
To TLS |
2 |
3 |
2 |
DTR |
To External |
4 |
6 |
6 |
DSR |
To TLS |
6 |
4 |
20 |
RTS |
To External |
7 |
8 |
5 |
CTS |
To TLS |
8 |
7 |
4 |
GND |
Common |
5 |
5 |
7 |
Note: This is a "null-modem" cable, not a straight-through cable.