jnford@UMAXC.WEEG.UIOWA.EDU (Jay Ford) (08/18/88)
At The University of Iowa, we have a need to use hardware flow control and carrier detection independently on our Annex ports. This is not an unreasonable expectation, and apparently not an uncommon one since this problem was discussed in a recent note sent to the info-encore mailing list. However, the Annex only allows the use of one of these schemes at a time: either carrier detection OR hardware flow control; not both. According to the "Annex Hardware Installation Guide", the pin/signal allocations are as follows: pin lead name lead description --- --------- ---------------- 1 chasis ground chasis ground 2 TxD transmit data 3 RxD receive data 4 NC not used (usually RTS) 5 CTS clear to send (low true) 6 NC not used 7 signal ground signal ground 8 NC not used (usually CD) 9 DTR data terminal ready There is neither an RTS lead required for hardware flow control nor a CD lead needed for true carrier detection. Also, the cables offered by Encore allow the following connections: Annex port 25-pin port use for cable ---------- ----------- ------------- CTS DTR null modem DTR CTS null modem CTS CD Hayes-style asynchronous modem DTR DTR Hayes-style asynchronous modem Neither of these cabling arrangements provides both hardware flow control and carrier detection. A solution to this problem is the use of the currently unused pins for RTS (pin 4) and CD (pin 8). This would allow for real carrier detection and RTS-CTS hardware flow control simultaneously. Of course, this would require corresponding software changes. Jay Ford Weeg Computing Center University of Iowa jnford@umaxc.weeg.uiowa.edu (319) 335-5555
robert@pvab.se (Robert Claeson) (08/18/88)
: At The University of Iowa, we have a need to use hardware flow control and
: carrier detection independently on our Annex ports. This is not an
: unreasonable expectation, and apparently not an uncommon one since this
: problem was discussed in a recent note sent to the info-encore mailing list.
Yup, try to connect a Trailblazer to an Annex without both hardware flow
control and modem control signals. Impossible, unless one has very bad
phone lines (which we don't have).
--
Robert Claeson Tel: +46 8-7300300
PVAB Fax: +46 8-7301567
P.O. Box 4040 Eunet: robert@pvab.se
S-171 04 Solna, Sweden Uucp: {uunet,mcvax}!enea!pvab!robertreading@utah-gr.UUCP (Dan L. Reading) (08/19/88)
Yes, I must agree. We need BOTH hardware flow control and modem control. We have had to throttle our 19.2K modems back to 9600 because of these "feature". -- Dan Reading Systems Programmer CS Dept U of U P.S. After expressing the above flame I should add that I'm basically pleased with the Annex boxes.