ITEM: AB1751L
128 controller problems
Question:
AIX: 3.2.5
DESC: 128 controller problems/remote hookup/performance degraded
Response:
Env:3.2.5 560 128port
Desc:Customer says terminals on remote RAN are slow the data burst to screen.
Act: I had him get his customer on line and I had her look at EC on RAN and
all LEDs were on I had her depress both arrow keys to reset error count and
you could see the leds incrementing. I fax him new cable drawing for
remote 128port. I had him to call PAC BELL to check lines.
NEW CABLE DRAWING
REDUCING SYNCHROUNOUS MODEM ERROR COUNTS on 128-Port Adapter
Some modems, when used to connect Remote Async Nodes (RAN), may require
external filtering to reduce error counts.
NOTE: To display the error count on the RAN, press the right arrow button
until an "EC" is shown on the RAN LED display. The front panel
lights display a binary representation of the number of errors
encountered. This can be cleared by pressing both the left and
right arrow buttons simultaneously thus allowing the count to start
over.
If high error counts are experienced, or the RAN exhibit difficulties in
downloanding then external filters should be installed.
Four 2200 pF capacitors (X7R 50V type) are required, two for the host
adapter, and two for the concentrator.
High Performance - CABLE NE
Description: 128-Port Async Controller Cable EIA-232 Modem Cable (System).
System End Modem End
HD-15 (Male) DB-25 (Male)
RxD 1-----(----------(----- 3 RxD
12-----(---Sgnd---(----- 7
* 5
RxC- 4-----(----------(-----17 RxC
12-----(---Sgnd---(----- 7
TxD- 6-----(----------(----- 2 TxD
12-----(--Sgnd----(----- 7
** 10
TxC 9-----(----------(-----15 TxC
GND 12-----(---Sgnd---(----- 7 SG
+-- 4 RTS
|
+-- 6 DSR
|
+--20 DTR
Shell ---------------------- 1 GND, Shell
Cable Shield
NOTES:
+ Physical connection
( twisted pair !!!!!!!!!!!!!!!!!!!!!!!!!!!
* a 2200 pf cap across pins 4 and 5
** a 2200 pf cap across pins 9 and 10
. Drain wire of cable shield tied to shells on both connector and into pin
1 of the DB25
. Each signal is paired with a Sgnd (signal ground). Sgnd tied together
at each end of the connector and on pin 7 (DB-25) and pin 12 (DB-15) on
the other end
. pins 4, 6 and 20 tied together. DSR of modem will drive RTS and DTR
CABLE NF
Description: 128-Port Async Controller Cable EIA-232 Modem Cable (Device).
Modem End System End
DB-25 (Male) HD-15 (Female)
RxD 3------(--------(------- 6 RxD
7------(--Sgnd--(------- 12
10 *
RxC 17------(--------(------- 9 RxC-
7------(--------(------- 12
TxD 2------(--------(------- 1 TxD-
7------(--------(------- 12
5 **
TxC 15------(--------(------- 4 TxC
SG 7------(--------(------- 12 GND
1, Shell ---------------------- Shell
Cable Shield
RTS 4----+
|
DSR 6----+
|
DTR 20----+
NOTES:
+ Physical connection
( twisted pair !!!!!!!!!!!!!!!!!!!!!!!!!!!
* a 2200 pf cap across pins 4 and 5
** a 2200 pf cap across pins 9 and 10
. Drain wire of cable shield tied to shells on both connector and into pin
1 of the DB25
. Each signal is paired with a Sgnd (signal ground). Sgnd tied together
at each end of the connector and on pin 7 (DB-25) and pin 12 (DB-15) on
the other end
. pins 4, 6 and 20 tied together. DSR of modem will drive RTS and DTR
This information can be provided to a local custom cable manufacturer in
order for them to build a cable that should solve communication errors
(shown by the error count (EC) led on the RAN) when the RAN are connected
via modems.
Next:closing
Support Line: 128 controller problems ITEM: AB1751L
Dated: August 1994 Category: N/A
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