GatesAir
DA-191B Four-Port Asynchronous Data Module
Intraplex Products
Version 1
4
2.2
Transmit Side
The DA-191B converts asynchronous data to a format appropriate for transmission over T1, E1
(2 Mbps), or other digital circuits made up of 64 kbps time slots. Data interface can be either RS-
232C or RS-449/422, depending on the module adapter installed (see Appendix A).
The Intraplex Logic Array contains four transitional coders, one for each port. When a coder
detects a change in the state of the data, it generates a three-bit word containing information about
that transition. The transmit data is sampled at 256 kHz for 38.4 kbps, 128 kHz for 19.2 kbps
operation, or 64 kHz for 9.6 kbps operation.
The resulting bitstream passes via the shelf backplane to the common logic module, which
multiplexes the data into the aggregate signal for transmission.
When used with an RS-232 module adapter, the transmit side of the module has a Clear to Send
(CTS) lead for each of the four ports. This signal is always on, and cannot be controlled by RTS.
A green
DATA IN
LED lights when active transmission begins on any active channel and
remains lit while transmission continues.
2.3
Receive Side
The multiplexer common module demultiplexes the aggregate receive signal and passes the data
for the selected time slot to the DA-191B module.
When used with an RS-232 module adapter, each port has a Carrier Detect lead which is on
during normal operation. While Carrier Detect is on, the module performs transitional decoding,
retimes the data, and separates the data channels if more than one data port is active. If the
multiplexer loses frame synchronization, all Carrier Detect leads are turned off, and all data ports
are set to MARK.
Each channel then goes to an RS-232 line driver, which converts it to RS-232 level and passes it
to the module adapter. On an RS-232 module adapter, the RS-232C output signal is sent to the
output connector. On an RS-449 module adapter, the RS-232 signal is first converted to RS-
449/422 and then sent to the output connector.
When the
LOOP
switch is activated, the receive data coming out of the Intraplex Logic Array is
looped back to the transmit input. A green
DATA OUT
LED lights when on any active channel
begins receiving data and remains lit while reception continues.
2.4
Alerts/Alarms
The DA-191B sends no Alert or Alarm signals to the shelf common card.
