44202-0898 <90-00004>
P
AGE
5
Power Supply
The regulated power supply provides:
♦
+5 VDC
♦
-5 VDC
♦
+12 VDC
♦
-12 VDC
These voltages are derived from a -21 to -56 VDC input source.
CIRCUIT DESCRIPTION
APPLICATION INFORMATION
A
pplications for the 44202 202 Compatible Modem consists of
digital data transmission service between distant equipment
sites. The 44202 can be used together with other manufacturers
equipment (alarm and control, for example) for transmitting and
receiving data between remote locations and a central location,
where the need for a DC powered modem exists. The 44202 does
not need to be interfaced with another 44202. It can be interfaced
to any modem operating under one of the following standards:
♦
Bell 202 (4-wire only)
♦
Bell 103 (2- or 4-wire)
♦
CCITT V.23 (4-wire only)
♦
CCITT V.21 (2- or 4-wire)
Example Application
Refer to Fig. 2. This application has one 44202 modem at a remote
location being used to transmit 460 Alarm and Control System
data to a 49013 202 Modem subassembly at a central data process-
ing location. Because the 44202 uses a DC power source, it can
provide stable operation when supplied by a battery that is inde-
pendent of AC power interruptions. The 44202 may also be used
with a 44124 Data Channel Termination Module, which provides
data channel line conditioning
