-CTS
-RTCLK
-TTCLK
-CD
-RRCLK
+CD
DGND
+DSR
+CTS
+RTS
+RXD
+TXD
CGND
13
12
11
10
9
8
7
6
5
4
3
2
1
25
24
23
22
21
20
19
18
17
16
15
14
CGND
+TTCLK
-RTS
-RXD
SYNCA
+DTR
-TXD
CGND
+RRCLK
-DTR
+RTCLK
-DSR
Figure 2 --- MPAP-200 Output Connector Pinout
19.1 SYNCA (pin 21)
If EXTSYNC (bit 6) in the Communications Register is set to a logic 1, the SYNCA
signal from the connector is used to drive the active-low SYNC input of SCC channel A.
This is
a single-ended input
, inverted by the receiver, so a +5 volt signal on pin 21 will assert SYNCA
(a -5 volt signal will deassert SYNCA). The SCC must be specifically programmed to recognize
external synchronization.
19.2 MPA-200 and EIA-530 Compatibility
The MPAP-200 is designed to be functionally-compatible with Quatech's MPA-200 DTE
adapter for the ISA bus. The MPAP-200 connector pinout varies slightly from that of the
MPA-200, with the local and remote loopback output signals (LL and RL) and the test mode
input signal (TM) replaced with a SYNCA input and two ground conductors.
If the MPAP-200 is to be connected to an EIA-530 device, it may be necessary to swap
the +/- conductors on the TXD and RXD signals.
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