P
AGE
2
49213-1297 <90-00094>
ORDERING INFORMATION
NOTE:
This section lists the different options available for this product. To order any of the avail-
able options, contact Dantel Inside Sales through our toll-free number,
1-800-432-6835.
OPTION NUMBER
FEATURES
B12-49213-00
Smart Block 202 Modem
GENERAL DESCRIPTION
T
he Dantel 49213 202 Modem Subassembly (49213 Modem)
converts digital data into frequency shifted tones and enters
the data into a data transmission system. Conversely, the 49213
Modem receives frequency shifted tones for a transmission
system and converts the tones into digital data.
The 49213 Modem operates as a Bell 202 full-duplex modem
with a data rate of 1200 baud.
NOTE
: The 49213 Modem is used exclusively with Dantels 46210
Alarm Block (46210 AB) or 46220 Alarm and Control Block
(46210 ACB).
CIRCUIT DESCRIPTION
F
ig. 1 shows the 49213 202 Modem Subassembly functional
schematic.
Subassembly input tones (RXD) appear at pins 3 and 4 of
connector P10. The tones couple to the subassembly through a
600:600 ohm transformer. The signal applies to the modem
integrated circuit chip, which controls the receive (RXD), clear to
send (CTS) and data carrier detect (DCD) to the 46210 AB or
46220 ACB.
The integrated circuit (IC) chip receives 46210 AB or 46220 ACB
transmit (TXD) and request to send (RTS) signals. The IC chip
sends tones through a 600:600 ohm transformer to the transmit
(TXD) output at pins 1 and 2 of connector P10. You can adjust
the tone level with strap X1 and potentiometer R8.
A test switch (S1) grounds the RTS lead which turns on the
opposing (distant end) modem DCD and causes data carrier
transmission. Each modem verifies the presence of the data
carrier, which allows level adjustment without the presence of
data. Shorting pins 7 and 8 of connector P10 also activates the
