
NT1B-300TC-TSG
Installation
Instructions
The Tone Commander 
NT1B-300TC-TSG converts 
an ANSI standard 2B1Q 
ISDN U-interface from the 
telco Central Office to an 
S/T interface to connect to 
local customer terminal 
equipment. Both 
point-to-point and multipoint 
ISDN terminal equipment 
configurations are 
supported.
The NT1B-300TC-TSG is 
intended for use in 
standalone applications 
with TSG-6 approved S/T 
interface ISDN terminals, 
such as the L3 
Communication Systems 
STE, or the Tone 
Commander 6220T-TSG, 
where the NT1 is collocated 
within the SCIF area.
This model complies with ANSI T1.601-1992 and T1.605-1991 
interface standards, including MLT (Mechanized Loop Testing) 
requirements, and is compatible with National-1 and National-2 
ISDN standards. The NT1B-300TC-TSG is a modified version 
of the Tone Commander NT1B-300TC, with special hardware 
modifications to support TSG security requirements.
Complete metallic disconnection of the U interface on the ISDN 
Line jack is provided when the NT1 is not powered, and the 
design ensures that unintentional microphonic audio signals are 
not detectable on external wiring.
Specifications
Operating Voltage ..............................34–56.5 VDC
Power Consumption.............................0.95 W typical,
from included 901034 Desktop Power Supply
Physical Dimensions ...........................4.5“ x 2.1” x 1.1“
Weight ...............................................4oz.
Operating Temperature....................0°–50°C(32° – 122° F)
Humidity ...........................5%to95%, non-condensing
Standards Compliance ............ANSI T1.601-1992, T1.605-1991
FCC Part 15, Part 68
UL, cUL Listed
FCC Requirements
The Tone Commander NT1B-300TC-TSG has been tested and 
found to comply with the limits for a Class B 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 residential 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. However, 
there is no guaranty that interference will not occur in a particular 
installation. If this equipment does cause harmful interference to 
radio or television reception, which can be determined by turning 
the equipment off and on, the user is encouraged to try to correct 
the interference by one or more of the following measures:
Where it can be done safely, re-orient the receiving television or
·
radio antenna.
To the extent possible, increase the separation between the
·
telephone equipment and the television, radio, or other 
equipment.
If your telephone equipment runs on AC power, plug your product
·
into an AC outlet that is not on the same circuit as the one used 
by your radio or television receiver.
The Tone Commander NT1B-300TC-TSG complies with Part 68 of 
the FCC Rules. The label affixed to this equipment contains, among 
other information, the FCC Registration for this equipment. You 
must, upon request, provide this information to your telephone 
company
The following jacks must be ordered from the telephone company in 
order to interconnect this product with the public communication 
network: RJ49C. A plug and jack used to connect this equipmrnt to 
the premises wiring and telephone network must comply with the 
applicable FCC Part 68 rules and requirements adopted by the 
ACTA.
If your NT1B-300TC-TSG causes harm to the telephone network, 
the telephone company will notify you in advance that temporary 
discontinuance of service may be required. But if advance notice 
isn't practical, the telephone company will notify the customer as 
soon as possible. Also, you will be advised of your right to file a 
complaint with the FCC if you believe it is necessary.
Your telephone company may make changes in its facilities, 
equipment, operations or procedures that could affect the proper 
functioning of your equipment. If this happens, the telephone 
company will provide advance notice in order for you to make 
necessary modifications to maintain uninterrupted service.
Repair work on this unit must be done by the manufacturer, Teo.
Connectors
Two terminal connectors are provided for convenient terminal 
installation; both are parallel connected to the S/T interface.
Important Safety Instructions
!
·
Never install telephone wiring during a lightning storm.
·
Never install telephone jacks in wet locations unless the jack 
is specifically designed for wet locations.
·
Never touch uninsulated telephone wires or terminals unless 
the telephone line has been disconnected at the network 
interface.
·
Use caution when installing or modifying telephone wires.
·
Only power the NT1 from the included Tone Commander 
Desktop Power Supply (Model 901034).
·
Do not mount the NT1B-300TC-TSG within 12“ of a heat 
source.

Termination Switch
Installation and Troubleshooting
The termination switch is located on the front of the NT1. 
Available settings are OFF, 100W, and 50 W .
Set the termination switch to match the premises wiring 
between the NT1 and the terminals. Several typical wiring 
configurations are shown below, with the appropriate 
termination switch setting.
Fixed or adaptive timing selection is not required.
The use of Category 3 or better unshielded twisted pair 
cable with T568A or T568B connector wiring is 
recommended. Distances shown are maximum for 
24-gauge wiring cable, and may vary for other cable types.
Connect the network U interface from the telco to the U LINE 
jack on the NT1. Connect ISDN BRI terminals to either S/T jack 
using four pair unshielded twisted pair (UTP) cable, Category 3 
or better, with T568A or T568B wiring.
After the U and S/T cords are connected, connect the power 
source to the NT1. Observe the indicator LEDs. The green 
POWER LED should turn on as soon as power is applied. The 
green STATUS LED should transition from off, to fast flash, slow 
flash, then on steady as the U and S/T interfaces initialize. The 
NT1 is fully activated when both LEDs are on steady. Be 
patient; in some instances, the network may take up to 3 
minutes to synchronize with the NT1.
If two S/T terminals are connected to the NT1, the STATUS LED 
will light steady if either terminal has initialized through the NT1. 
To check each terminal, connect only one at a time and verify 
LED status.
Incorrect termination on the S/T (terminal) interface is a 
common cause of unreliable terminal operation. Symptoms 
include random data errors, intermittent STATUS indication, or 
complete terminal malfunction. Network line synchronization 
may not be affected. Refer to the wiring configuration diagrams 
in the Termination Switch section for the appropriate termination 
setting.
To fully operate with the network, the terminal equipment must 
also be correctly programmed with required operating 
parameters (such as SPID) that are provided by your telco. 
Consult your terminal equipment documentation for 
programming instructions.
Power Connections
The NT1B-300TC-TSG must be powered by the included Model 
901034 Desktop Power Supply. Plug the power supply barrel 
connector into the POWER jack on the NT1.
Terminal power is supplied through the NT1 for either of the 
following configurations:
PS2 - Direct power feed on S/T jack pin 7 (-) and pin 8 (+), 
5 watts maximum per terminal (10 watts total).
PS1 - Phantom power feed over the transmission pairs, S/T 
jack pins 3/6 (+) and pins 4/5 (-), 4 watts maximum (total for all 
terminals).
Status Indicators
The operating state of the NT1B-300TC is displayed by the two 
indicator lamps.
POWER: ON STEADY when power is applied to the NT1.
STATUS: OFF – No U interface (line error). Check connection
to telco network.
FAST FLASH (8/sec.) – Attempting to link U interface with the 
telco network. A fast flash persisting longer than 15 seconds 
indicates that the NT1 is in a maintenance mode that was 
requested by the central office
SLOW FLASH (2/sec.) – U linked, S/T link not established with 
terminal. Check connection to terminal.
ON STEADY – Normal operation. U linked, and at least one S/T 
terminal linked.
Resetting the NT1
If the U interface is disconnected or disrupted, a loss of linkage 
between the NT1 and the telco central office may occur. To 
force immediate network and terminal resynchronization, 
momentarily disconnect power to reset the NT1.
Removing power from the NT1 during normal operation will 
temporarily disrupt network communication and will disconnect 
any call in progress.
Teo Product Warranty
For a period of one year from date of end user purchase, but 
not to exceed 16 months from date of manufacture, Teo 
Technologies, Inc. warrants its products to be free from defects 
in material and workmanship under conditions of normal use 
and service. Warranty details are available on our Web site, 
www.teotech.com.
Tone Commander Systems has changed 
its name to Teo Technologies.
11609 49th Place West – Mukilteo, WA 98275-4255
(800) 524-0024 (425) 349-1000 Fax: (425) 349-1010
13-280128 Rev. B
February 2012
www.teotech.com