kjh@pollux.usc.edu (Kenneth J. Hendrickson) (12/01/90)
I recently ordered a Practical Peripherals 9600SA modem from a mail order house on the east coast. Since they were out of stock, and since a local company had a policy of 100% refund for any reason within 30 days, I decided to go get one there and try it out. Initially, I was very pleased. It was plug and play. It supports V.32, V.42, V.42bis, MNP2-4, and MNP5. I had no difficulty at all dialing up the University's V.32 modems (MNP5). 9600 bps was sure a lot nicer than 2400 bps. I played with the registers allowing Data Compression and Error Correction. I found that _disallowing_ Data Compression yielded higher data transfer rates! This was true both for compressed files (.ZIP) and for text files. This was suprising, especially in the case of text files. Then I tried to call the University's 2400 bps modems using the 9600SA. I experienced lots of noise problems. I couldn't get a connection. I RTFM, and RTFM some more. I played with many of the S registers. Still, the noise problems existed. Since I had experienced some noise problems before with my 2400 bps modem, I got out my 2400 bps modem again to see what it would do. It worked just fine. Trying the 9600SA again showed it couldn't handle the connection at all. I switched the modems 4 or 5 times within a time period of about 1 hour, and each time the 2400 bps modem worked just fine, while the PPI 9600SA couldn't hold the carrier. I will call the PPI Tech Support number tomorrow (or maybe Monday) to see if I have done something stupid. If they cannot solve the problem, I will return the modem, and cancel my order with the mail order house. There are many existing 2400 bps modems, and if I can't connect with them, I consider the PPI 9600SA modem unacceptably broken. I hope the Intel modem has better performance. After this experience, I have had a couple of problems with the 9600SA on a 9600 bps connection. Occasionally, I will hear a couple of relay clicks out of the modem, and while the LEDs stay on indicating OH and Carrier Detect, the modem connection is non-existant. Even after waiting 30 seconds or so to allow for retraining showed that the modems are not connected any more, despite the front panel lights. This has happened probably 2 or 3 times over about 50 login attempts. Conclusions: The PPI 9600SA is _USELESS_ at speeds under 9600 (4800) bps. I consider this absolutely unacceptable. Disallow Data Compression for higher data transfer rates, on ALL types of files! Errata: issuing the ATI3 command shows the modem is: PM9600SA Version 1.05 (c) Practical Peripherals, Inc. 1990 My existing 2400 bps modem is an Avatex 2400. -- favourite oxymorons: student athlete, military justice, mercy killing Ken Hendrickson N8DGN/6 kjh@usc.edu ...!uunet!usc!pollux!kjh
root@zswamp.fidonet.org (Geoffrey Welsh) (12/01/90)
Kenneth J. Hendrickson (kjh@pollux.usc.edu ) wrote: >I found that _disallowing_ Data Compression yielded >higher data transfer rates! This was true both for compressed files >(.ZIP) and for text files. This was suprising, especially in the >case of text files. In the case of .ZIP, .ZOO, .Z, LZH, etc. files, this should be no surprise to those who have been reading postings by myself and numerous others on the topic of MNP5 and precompressed data. On the other hand, I am puzzled by your results with text files. Were you using a non-streaming protocol (such as Kermit, XMODEM, etc.)? Higher levels of MNP can diminish interactive throughput; MNP5 should provide a significant boost to text file transfers using streaming protocols such as ZMODEM. >Then I tried to call the University's 2400 bps modems using the >9600SA. I experienced lots of noise problems. I played with a USRobotics Courier HST (version 964) for nearly a year before concluding that the HST's 2400 stank. I do not have the same problems with my Evercom 940 (Everex internal 1/3-length 2400) or my Hayes Smartmodem 2400. >I hope the Intel modem has better performance. We all hope, but it's been my experience that most of the low priced 9600 bps modems have as their single goal 9600 bps performance; in many cases the 2400 bps circuits used do not seem to have been adjusted for use with the (different) electrical characteristics of the 9600 bps circuits. This has the sad effect of doing real damage to the 9600's non-9600 bps performance. -- UUCP: watmath!xenitec!zswamp!root | 602-66 Mooregate Crescent Internet: root@zswamp.fidonet.org | Kitchener, Ontario FidoNet: SYSOP, 1:221/171 | N2M 5E6 CANADA Data: (519) 742-8939 | (519) 741-9553 MC Hammer, n. Device used to ensure firm seating of MicroChannel boards Try our new Bud 'C' compiler... it specializes in 'case' statements!
kjh@pollux.usc.edu (Kenneth J. Hendrickson) (12/03/90)
In article <6058.27588AA8@zswamp.fidonet.org> root@zswamp.fidonet.org (Geoffrey Welsh) writes: >Kenneth J. Hendrickson (kjh@pollux.usc.edu ) wrote: > >I found that _disallowing_ Data Compression yielded > >higher data transfer rates! This was true both for compressed files > >(.ZIP) and for text files. This was suprising, especially in the > >case of text files. > On the other hand, I am puzzled by your results with text files. Were you >using a non-streaming protocol (such as Kermit, XMODEM, etc.)? Higher levels >of MNP can diminish interactive throughput; MNP5 should provide a significant >boost to text file transfers using streaming protocols such as ZMODEM. I was using zmodem. MNP5 made throughput worse with text files! I can't explain this. > We all hope, but it's been my experience that most of the low priced 9600 >bps modems have as their single goal 9600 bps performance; in many cases the >2400 bps circuits used do not seem to have been adjusted for use with the >(different) electrical characteristics of the 9600 bps circuits. This has the >sad effect of doing real damage to the 9600's non-9600 bps performance. Can anybody recommend a good V.32 9600 bps modem that also has at least useable performance at V.22bis, and V.22? As reported before, My Practical Peripherals PM9600SA rev 1.05 is TOTALLY UNUSABLE at 2400 bps and 1200 bps. I have corresponded with some others who also have this modem by email, and at least one person is able to use it at 2400 bps. Perhaps I just got a bad sample. However, I feel that the "black eye" that I have given Practical Peripherals over their totally non-usable 2400 and 1200 bps performance is well earned on their part. If their engineers knew that the 2400 and 1200 bps performance would be lousy (and I have to believe that they were cognizant of that fact) then it probably would have been better that the modem didn't even support V.22 and V.22bis. There is another problem with the Practical Peripherals 9600SA. Occasionally, when the modem takes a hit of line noise, the carrier will be lost. When this happens, a couple of relay clicks are heard from the modem, and data communications is lost, but the OH and CD lights stay on! The modem doesn't respond to lowering the DTR line (I have done "at &d2", nor does it respond to the "+++" sequence to return to command mode. There is no way to get ahold of the modem any more other than cycling the power. This is OK for interactive use, but it is totally intolerable for non-interactive use like getting a news feed or mail via uucp or some other means. My recommendation: I can't recommend the Practical Peripherals 9600SA. -- favourite oxymorons: student athlete, military justice, mercy killing Ken Hendrickson N8DGN/6 kjh@usc.edu ...!uunet!usc!pollux!kjh
burris@highspl (David Burris) (12/03/90)
From article <28577@usc>, by kjh@pollux.usc.edu (Kenneth J. Hendrickson): > > Can anybody recommend a good V.32 9600 bps modem that also has at least > useable performance at V.22bis, and V.22? As reported before, My > Practical Peripherals PM9600SA rev 1.05 is TOTALLY UNUSABLE at 2400 bps > and 1200 bps. I have corresponded with some others who also have this > modem by email, and at least one person is able to use it at 2400 bps. I am responding to this article using a 9600SA at 2400/MNP4. I have gotten it working fairly well. I'm able to talk at 1200 as well. I'm still working on faster connections. > > There is another problem with the Practical Peripherals 9600SA. > Occasionally, when the modem takes a hit of line noise, the carrier will > be lost. When this happens, a couple of relay clicks are heard from the > modem, and data communications is lost, but the OH and CD lights stay > on! The modem doesn't respond to lowering the DTR line (I have done > "at &d2", nor does it respond to the "+++" sequence to return to command > mode. There is no way to get ahold of the modem any more other than > cycling the power. This is OK for interactive use, but it is totally > intolerable for non-interactive use like getting a news feed or mail via > uucp or some other means. I'm getting a news feed using the 9600SA at 2400/MNP4 and so far am having no problems. I'll post an opinion about this modem after a week or two of steady operation. I'll also send the settings/modes once I get everythig going. > > My recommendation: I can't recommend the Practical Peripherals 9600SA. > Me either...yet! The modem is going into service full-time at 1200, 2400, 2400/MNP4 as I type, faster speeds later. -- ================================================================ David Burris Aurora,Il. burris@highspl {att | uunet}!linac!highspl!burris ================================================================
cec@cup.portal.com (Cerafin E Castillo) (12/04/90)
TELEBIT is in the process of announcing the T1600 V.32 modem at
a list price of $795 US. This V.32 modem is a second generation
product for TELEBIT with a proprietary DSP implementation of V.32
and not the Rockwell ChipSet. This V.32 modem features V.42/V.42bis
MNP 4/5, V.22bis, V.22, Bell 212, Bell 103. Protocol support for
UUCP/Kermit/X+Y-modem in V.32 mode, as well. I KNOW, being a
Telebit user, that this modem will work at 2400/1200/300 reliably,
as well as fallback to 4800 in V.32 mode, without disconnecting.
Give me a buzz if interested (please pardon the salesy tone, I am
an authorized and stocking Telebit distributor ;-).
===============================================================================
Cerafin E. Castillo || //\\ ||\\ ||
Network Consultant || //__\\ || \\ || Los Altos
Los Altos Networks || // ---\\|| \\|| Networks
340 Second St. #6 ||___// \ | \ |
Los Altos, CA 94022
(415) 941-8031 UUCP: {apple,sun,uunet}!portal!cup.portal.com!cec
INTERNET: cec@cup.portal.com
"...No hay mal que por bien no venga..."
===============================================================================reich@well.sf.ca.us (Richard Reich) (12/04/90)
kjh is having serious trouble, but I have to report that I have no trouble with my PM9600SA at 2400 -- and, unfortunately, 2400bps usage constitutes about 95% of my total telecomming at the moment. Do not disregard the PM9600SA without trying it. -r (Only connection with PPI: satisfied customer)
kjh@pollux.usc.edu (Kenneth J. Hendrickson) (12/04/90)
In article <25717@uflorida.cis.ufl.EDU> dwatney@pine.circa.ufl.edu writes: >In article <28577@usc>, kjh@pollux.usc.edu (Kenneth J. Hendrickson) writes... >>I was using zmodem. MNP5 made throughput worse with text files! I >>can't explain this. > >Any chance that you had the zmodem compression option on? Only if it is the default. I don't know how to turn it on, and I have never used it. I highly doubt that the zmodem protocol was doing any compression, but I could be wrong. -- favourite oxymorons: student athlete, military justice, mercy killing Ken Hendrickson N8DGN/6 kjh@usc.edu ...!uunet!usc!pollux!kjh
lriggins@blackbird.afit.af.mil (L. Maurice Riggins) (12/07/90)
In article <21933@well.sf.ca.us> reich@well.sf.ca.us (Richard Reich) writes: | |kjh is having serious trouble, but I have to report that I have no trouble |with my PM9600SA at 2400 -- and, unfortunately, 2400bps usage constitutes |about 95% of my total telecomming at the moment. | |Do not disregard the PM9600SA without trying it. | |-r |(Only connection with PPI: satisfied customer) I have to agree, I've had NO problems with the PM9600SA at any speed. I got one of the early models (so early it had a temporary manual with a postcard to order a real one :-) Hooked it up to a Mac SE with hardware handshake cable and proceded to do justice to the UDS 9600 MNP's on our net. I did hear on the net that there was some handshake problems when used with Macs, so I sent it back for the update and they returned it Blue Label. I'm even testing it successfully with COUNTERPoint/Copernicus on a USR HST Hermes BBS, so the only speed we have in common is 2400. However, both speak v.42 with no problem. I also regularly connect with a non-Ultra Hayes V-Series 9600 (at 2400 baud), an Avatex 2400, and the Gandalf 2400's on our net. No problems with any of these before or after the "Macintosh Update." Considering the cost difference between a USR or Hayes and the PP, it's definitely worth testing. -- Maurice INTERNET: lriggins@blackbird.afit.af.mil (129.92.1.2) Opinions expressed here do not reflect those of my employer nor constitute an official position of any U.S.Government agency.