TM 11-7025-234-23
Section Il. EQUIPMENT DESCRIPTION AND
DATA
The V.29 modem conforms to EIA RS-232C (CCITT V.24) recommendation V.29 and is
designed for use in both point-to-point and multipoint configurations over 4-wire
dedicated lines. The V.29 modem can:
Receive and transmit information between one ADP System and other ADP
systems or remote terminals
Process 9600 bps of serial synchronous digital input data for transmission
at a 2400, 1600, or 1200 baud rate
q Continue
to update 2400 times per second, (1600 times per second when a
1600 baud rate is selected) in a completely unattended data mode
Operate at 9600 bps or when deterioration conditions exist, drop to 7200
or 4800 bps
Data and Signaling Rates. The data rate of the V.29 modem unit is 9600 bits
a.
per second (bps) of serial, synchronous, binary data with a fallback capability to
7200, 4800, or 2400 bps. The V.29 modem has a 2400 baud line signaling rate
utilizing double side band, suppressed carrier, quadrature amplitude modulation
(QAM). Also available is a 4800 bps/1600 baud fallback mode and 2400 bps/1200 baud
fallback mode. Receive timing synchronization, automatic gain control (AGC)
setting, and equalization are maintained during line interruptions up to 10 seconds.
b. Transmit Output Level. The output level of the transmit output amplifier is
switch-selectable to configure to a variety of applications. Level may be set at
-16, -14, -12, -10, -8, -6, -4, or O dBm (fig. 1-6).
c. Receive Input Level.
The receive input level sensitivity is -40 to O dBm.
d. Equalizer Setup Time. During modem operation, the equalizer function
monitors the delay and amplitude characteristics of the data line, senses
differences due to transmission line changes and adjusts the delay and amplitude
accordingly. At 2400 baud the equalizer is set up within 253 ms; for 2400 baud
operation (9600, 7200, or 4800 bps) it is setup within 275 ms; at 1600 baud (4800
bps) it is set up within 140 ms, and at 1200 baud (2400 bps) it is set up within
153 ms.
e. Internal HF Oscillator. A 3.6864 MHz crystal oscillator having a long term
stability is used as a reference.
f.
Telephone Line.
The V.29 modem operates over 4-wire dedicated nines.
(1) In 2400 baud mode it requires a balanced 600-ohm, type 3002, C2
unconditioned telephone line or equivalent, with a normal 16 dBm loss and frequency
translation of up to 10 Hz.
