IBM Series 1 User Manual page 203

DPe ADAPTER DESIGN CONSIDERATIONS
The DPC adapter feature is used in applications requiring
access to the processor I/O channel. It does not provide
cycle steal capability. Therefore it is limited to direct
program control applica·tions.
Throughput would be a function of all system components.
The
end
user would add 2.5 microseconds
of
delay to the
throughput figure for his system configuration to arrive at
the data transfer rate at the
DPe
adapter interface.
Recommended
input dri ver:
Requirement:
Input
terminators:
TTL
open collector (SN75451 or equivalent)
Down level: +0.6 volt maximum
i
42 mA;
minimum current required at down level,
42 mA
ii)
+0.6 volts
150 ohm and 300 ohm divider network to +5 Vdc
± 101; effective terllination impedance equals
100 ohms
Note. Because this interface is non-isolated, it is
i.portant to ensure that there is a good ground connection
between the DEe device being attached and the card file
containing the DPC adapter feature card. If there is not a
good ground connection, a large co.mon-mode voltage mar be
developed, and damaqe ·to tbe device or feature card could
result.
The performance of this interface
may
be affected by
noise. Appropriate arc suppression, noise filtering, etc.,
may be necessary on the user's inputs.
The DPC adapter should be connected to a device with a
maximum o.f 6. 1
Bl
(20ft) o.f twisted-pair cable. Attachments
to the top-card connector must use a polarized serq1 housing
part number 65405-013 (or equivaleD~ and a contact part
number of 75598-003 (or equivalent) with .24 lWG wire.
The cable to the customer access panel feature can be
made using a 160-pin male connector block, Ampa part nomber
202799-2 (or equivalent), male contacts Amp part number
66101-1 (or equivalent), and .24 AWGvire.
The DPC adapter card connector pin assignment for
ground points should be 'followed at the device end of the
cable.
Diagnostic wrap capability is provided at all the DPC
adapter feature connection points for devices.
1Berg Electronics, Division of E.l. duPont de Nemoars, Co.
2Amp, Incorporated
6-22 GI34-00.33
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