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Table 2-9
R6684-17 Pin Descriptions (MDP) (continued)
Pin Name
Pin Type
MODEU Sterconnect (continued)
CLKIN
Dl
RMODE
Dl
TMODE
Dl
TXD
IA
RXD
OA
TDCLK
OA
XTCLK
IA
-RDCLK
OA
-RLSD
OA
-RTS
IA
-DTR
IA
-CTS
OA
-DSR
OA
Telephone Line Interface Signals
TXA1
O(DF)
TXA2 (NC)
RIN
I(DA)
RlNGD
IA
-RLYA
OD
(-OHRC)
Pin No.
33
Clock. Connect to IA_CLKIN.
44
Receiver Mode. Connect to TMODE.
45
Transmitter Mode. Connect to RMODE.DTE INTERFACE
57
Transmitted Data. Not used; pull up to VCC through 10k n
35
Received Data. Not used; leave open
50
Transmit Data Clock. Not used; leave open.
54
External Transmit Clock. Not used; leave open.
52
Receive Data Clock. Not used; leave open.
51
Received Line Signal Detector. Not used, leave open.
7
Request to Send. Not used; pull up to VCC through 10kΩ
34
Data Terminal Ready. Not used; pull up to VCC through 10k
n.
37
Clear to Send. Not used; leave open
58
Data Set Ready. Not used; leave open.
27
Transmit Analog 1 and 2. The TXA1 and TXA2 outputs are
26
differential outputs 180 degrees out of phase with each other.
Each output can drive a 300Ω load. TXA2 is not used
23
Receive Analog. RIN is a single-ended receive data input
from the telephone line/audio interface circuit
6
Ring Detect. The RINGD input is monitored for pulses in the
range of 15 Hz to 68 Hz. The frequency detection range may
be changed by the host in DSP RAM. The circuit driving
RINGD should be a 4N35 optoisolator or equivalent. The
circuit driving RINGD should not respond to momentary
bursts of ringing less than 125 ms in duration, or less than 40
VRMS (15 Hz to 68 Hz) across TIP and RING. Detected ring
signals are reflected on the -Rl output signal as well as the Rl
bit
31
Relay A (Caller ID) Control. The MDP -RLYA output is
connected to the Caller ID relay (DPDT). When Caller ID is
enabled, the modem doses the Off-hook relay and asserts
this output to switch the Caller ID in order to detect Caller ID
information between the first and second rings.
The -RLYA output can directly drive a +5V reed relay coil with
a minimum resistance of 360 ohms and having a must-
operate voltage of no greater than 4.0 Vdc. A clamp diode,
such as a 1 N4148, should be installed across the relay coil.
An external transistor, such as an MPSA20, can be used to
drive heavier loads (e.a., electro-mechanical relays).
Descriptions
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