BayPac
Model BP-1 Packet Modem
INTRODUCTION
The BayPac Model BP-1 comes completely assembled and tested. Installing it
is a two-step process. The first step involves connecting the BayPac to your
radio and computer. This document will help you thru that process. The
second step involves setting the transmit and receive audio levels. We have
provided a setup program on disk to make that task very easy. In addition,
you will of course need to install Baycom software on your computer. We
have supplied a complimentary copy of this software on our setup disk for
your convenience.
WHAT YOU WILL NEED
To run the Baycom software you will need an IBM PC/XT/AT or fully
compatible clone. To install the BayPac modem, your computer will need a
serial port. In addition you will need whatever connectors are required to
attach to the external speaker jack and microphone input on your radio.
These parts may have been supplied with your radio or may be purchased
from your local electronics dealer.
CONNECTING THE COMPUTER
If your computer has a DB-25 connector on its serial port (PC/XT), you
simply need to plug the BayPac into the connector. If your computer uses a
DB-9 connector, you will need an adapter cable. A suitable cable is available
from Tigertronics (Part # ADAPT-25M/9S) or from your local computer
store. If you wish to build the cable, refer to the diagram in Figure 1. Be sure
to remember whether you have connected to COM1 or COM2 on your
computer. You will need this information when running the setup program
and during Baycom software installation.
CONNECTING THE RADIO
There are only four wires required to connect the BayPac to a transceiver.
The connector pin-out is shown in Figure 2.
CAUTION Notice the orientation of the colored wires with respect to the
body of the connector. BE SURE that the cable you plug into the BayPac
does not have these wires in reverse order! Remember that when viewing the
connector from the rear, with the release lever on the top, the left most wire
MUST BE YELLOW.
If you only plan to receive packet (not transmit), you can simply connect the
Black ground wire and the Green audio input wire to the external speaker
jack on your radio or scanner as shown in Figure 3. These are the only
connections necessary to receive packet transmissions.
If you are connecting the BayPac to a transceiver, you will also need to
connect the PTT line (Red) to key the transmitter and the Audio Out line
(Yellow) to the microphone input. Exactly where these connections are made
will vary with each model of radio. Most base station and mobile radios of
recent manufacture have all the required connections (including the speaker
output) available on the microphone connector. This is the ideal situation
since it makes the cabling simple. If your radio does not have the speaker
connection on the mic connector you might consider modifying it so that it
does. You will find it worth the effort. You will need to refer to your radio
manual for the specific pins to connect to.
If your radio does not have the speaker signal on the mic connector, you will
need to run a short jumper cable to the external speaker jack. Note that
having the speaker cable exit from the mic connector housing (rather than
splitting the cable outside the connector) makes a much nicer installation.
Refer to Figure 4.
You should verify that your radio requires the PTT line to be grounded to key
the transmitter. This is the case for the vast majority of radios. The BayPac
expects to pull the PTT line to ground to enable the transmitter. The PTT
output is a FET transistor capable of sinking about 300 ma at 12 volts. If
your radio needs some other keying arrangement (not likely) you will need to
provide it.
HT OPERATION
If you are connecting the BayPac to an HT you may find that there is no PTT
line available. Many of these radios key the PTT by grounding the mic input
thru a resistor as shown in Figure 5. The value of the resistor is not critical. A
value of 4.7k ohms is generally acceptable. Refer to your radio manual for
specific recommendations. NOTE: When using your HT for packet, WE
STRONGLY RECOMMEND that you use AN EXTERNAL ANTENNA
located at least a few feet away from both the BayPac and the computer. The
connections on most HTs are a fraction of an inch from the antenna and will
almost certainly pick up enough RF to cause some sort of problem. Refer to
the section on RF Interference in this document for further information.
SETUP DISK
We have provided a disk with the BayPac modem that contains several files
of interest. Print or list the THISDISK.DOC file on the disk for an
explanation of each file. We have also supplied you with a customized copy
400 Daily Lane
P.O. Box 5210 Grants Pass, Oregon 97527 (503) 474-6700
FAX (503) 474-6703
TM
- INSTALLATION -
