Telos Zephyr, Руководство пользователя

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Section 11 TECHNICAL INFORMATION 213
ISDN S&U Interface Card (USA only)
Power Supply
The 48 volt power supply circuit (distinguished by U5, the Maxim MAX641) is
used to power either an external NT1 (if used) or an ISDN telephone which can
be plugged into the Zephyr.
The PS- 2 power available on Pins 7 and 8 of the S connector must be enabled on S&U
interface cards Rev B and later. To do so:
•
Find the jumper block labeled JP- 1 near the top of the board, on the
component side. If the jumper is on pins 2&3 PS- 2 power is off (default).
Moving the jumper to pins 1&2 will enable PS- 2 power. IN ANY CASE:
S-Interface
Connector J1, the 8 pin modular jack (labeled Phone/NT1), is used to connect an
external NT1 or an ISDN phone to the Zephyr™. Transformers T1, T2, T4, and T5 are
used to isolate outside telephone lines from the Zephyr circuitry, as well as step
up/down the voltages of analog signals. The Mitel MT8931B (U2) is used as the S-
Interface which defines the Zephyr as a Terminal Device (TA). It transmits the coded
audio data to the NT1 (network termination), whether internal or external. If an ISDN
phone is used, the phone and the Mitel chip share the same communication lines via
Time Division Multiplexing, the decoding of which is taken care of by the internal NT1.
U-Interface (NT1)
Connector J2, the 6 pin modular jack (labeled Line/Direct), is used to connect the
internal NT1 on the card to the Central Office (Telephone Company). Transformer T3,
the Valor PT4084, is used to isolate the Zephyr from the telephone line. The entire NT1
function is provided by the AT&T T7256 chip. 4 wires form the S/T interface of the NT1,
and another 2 form the U- Interface.
The U Card must be plugged into slot P1 (furthest right) on the Zephyr motherboard,
and system software revision 2.56 or later must by used (EPROM U4). The card can
either be used alone as a complete NT1 and TA (most common) or with an external
NT1 (e.g. Tone Commander) in the same way as the older ISDN card was used.
IMPORTANT!
If using an external NT1, or connecting another device, be
sure to check power arrangements. The Zephyr provides “PS-
2” power on the S/T jack. If your NT1 or other device has an
external power supply it is essential that the 2 power leads not
be interconnected or damage to the Zephyr, external
equipment, or both, may occur. Contact Telos Systems
customer support for additional information, if needed