CPI Communications DTP Series User Manual

Instruction Manual

DTP Series
DC Termination
Panels

Rev. B 9/00

DTP Series manual.p65

CPI Communications, Inc. • 941Hensley Lane • Wylie, TX 75098-4909
Phone [phone] • WATS [phone] • FAX [phone] or [phone]

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General Information

The CPI Communications DTP series DC remote adapters provide a reliable means of remotely controlling

a two-way radio base station or repeater over in-house or leased metallic pair wiring.

The DTP series can be used with CPI DC remotes as well as most other manufacturers DC remote consoles.
The DTP remote adapters are available in the following variations, all of which provide adjustable RX and

TX amplification and dip switch selection of control current format:

MODEL DESCRIPTION

DTP1 Board only product, provides PTT.

DTP2 Board only product, provides PTT and monitor functions.

DTP3 Board only product, provides PTT, monitor, F1/F2 functions.

Installation

Connect the leased or in-house metallic twisted-pair 600 ohm line, to the DTP board via J2. (the RJ-11 jack)
Connect an external 12 to 16 volt semi-regulated DC power supply to J1 with the positive lead to J1-2 and

the negative lead to J1-7.

Connect the radio receiver audio output to J1-6. Radio receiver audio output should be a source that is after
the squelch circuit and not affected by the radio's volume control adjustment. If a squelched audio source is not
available there is a squelch circuit provided on the DTP series termination panels. J1-5 is the input to the DTP's
squelch circuit. It can be configured active high or active low using jumpers JU14 and JU15.

Connect the radio microphone input to J1-1. If microphone input is high-impedance, shielded cable should
be used and R65 on the DTP board should be clipped. If a local microphone is used the mic high should be
connected to J1-3.

If you have a DTP2, connect the monitor circuit of the radio to the DTP2 board using the form "C" relay
contacts at J1-8, J1-9, and J1-10.

Connect the radio PTT circuit to the DTP at J1-4. For radios that key to a positive voltage instead of ground,
the PTT circuit can be altered using JU1 and JU2.

The DTP3 provides a form "C" set of relay contacts at J1-12, J1-13, and J1-14 for two channel frequency
selection. The relay output is factory set to be momentary. This can be changed to latching by using JU-16. The
DTP1 and DTP2 do not provide these contacts.

Level Adjustments

The following level adjustments are normally required only at the time of installation.

1. RX Audio Adjustment

R57 controls the RX audio level to the phone line. With the phone line connected at J2, connect a RMS
voltmeter to the leads of R61 and R62. Unsquelch the receiver so that continuous noise is present and adjust
potentiometer R57 for 0 dBm or 0.8 V rms on the meter.

2. TX MOD Adjustment

This section assumes that each remote in the system has been set to provide an average voice audio level
of 0 dBm as measured at the DTP panel.

Have someone at the remote control console depress and hold the PTT switch. With a voice coming from
the remote, adjust R47 to provide proper transmitter deviation.

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Switch Settings

The following table lists dip switch setting for DTP series.

DC Remote Provides Set Switches

PT T (F1) PT T (F2) Mon (F 1) Mon (F 2) 1 2 3

DTP1, DTP2

& DTP3

DTP2 & DTP3 +/- 15mA +/- 6mA OFF ON OFF

DTP3

Dip switch 4 is normally in the OFF position. When in the ON position, The perceived polarity of the phone
lines is reversed.
Modulation output is adjustable from 2 mVRMS to 565 mVRMS with 0 dBm on the phone lines. The phone
lines can be driven to 0 dBm with an RX input level from 88 mVRMS to 880 mVRMS. A 0 dBm level on the
phone line back to the remote can be produced with a mic high input between 2 mVRMS and 565 mVRMS.

+/- 15mA OFF OFF OFF

+/- 6mA ON OFF OFF

+ 15mA -6 mA ON ON OF F

+/- 6mA +/- 2.5mA OFF OFF ON

+ 6mA - 2.5mA ON OFF ON

+ 6mA + 15mA - 2.5mA - 2.5mA OFF ON ON

+ 15mA - 15mA + 6mA - 6mA ON ON ON

Parts List

DTP Series PCB #700-DTPX-200 Rev. B

Reference Description CPI Part #

CAPACITORS

C1,18 100uF Elec Rad 208-2021-107
C2,3,5,15,16 .1uF Mono Cer Dip 208-0092-104
C4 10uF Elec Rad 208-4022-106
C6,27 1uF Elec Rad 208-4052-105
C9,10 4.7uF 100V Elec Rad 208-2062-475
C11,12 20pF Cer 208-0001-200
C13,14,17,21,22 .01uf Mono Cer Dip 208-0092-103
C23 180pF Mono Cer Dip 208-0071-181
C24 .047 Mono Cer Dip 208-0092-473
C25 2200pF Mono Cer Dip 208-0071-222
C26 1uF Elec Rad Non-Polar 208-2000-001
C28 2.2uF Elec Rad 208-4052-225

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