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Transcript on a seminar about Telepathy

Last Updated on June 2, 2020 by


 

Transcript on a seminar about Telepathy

The Gateway TelePath Fax/Modem: “Which Rumors are True and Why Most are Not” Tim Gilbert, Gateway 2000 Product Development

The Gateway “TelePath” modem has raised a lot of questions lately. I don’t have time or space to get into the eye patterns, trellis coding and everything else, but this memo should put most of the rumors to rest.

Overview: The TelePath is a 14,400 bps fax/modem designed by Gateway using the latest Rockwell chip set. The actual boards are assembled in Rapid City, SD. by a major board house under contract to Gateway. The design uses a C19 Rockwell controller, RC144 Digital Signal Processor, two PROMs and miscellaneous support chips. The maximum data transfer between the modem and the host computer is actually 115.2 kbps, but this is beyond what the data compression routine can utilize; therefore, there is no reason to set the DTE speed higher than 57,600.

Bad Chips: Rumor has it that Rockwell shipped defective silicon. This is completely false! However, there was a bug in the original firmware that affected the fax handshaking. (firmware: software contained in PROMs. It is used by the on-board processor; similar function as the BIOS on your mother board.) Unfortunately, it caused problems with a small number of fax machines. I say “unfortunately” because, in keeping with Murphy’s philosophy, we didn’t have those models, (i.e. Pitney Bowes), in our compatibility test lab at the time; nor did our Beta test sites; neither did Rockwell. (With the incredible number of machines out there, it is impossible to perform exhaustive testing.) Needless to say, the first customer who tried to fax found one. If you’re just using the TelePath as a modem you wouldn’t have noticed a problem.

Backorders: The modem is backordered. This is a result of the firmware issue as well as some component availability issues. (In the volume we order things, there are very few vendors who can keep up.) Of course, there is also the general overload of orders. Modems will be shipped on a ‘first ordered, first sent basis’ and we expect to have the factory up to full speed very soon.

TelePath: To the best of my knowledge (and that of our legal department), there is no such company as “TelePath,” nor is this card available under anyone else’s label. It is just a name that Ted Waitt used to refer to the modem. And since everyone in the whole company thought it was the most brilliant marketing idea since Sam Morse started this whole mess, it stuck. Send the modem an ‘ATI3’ (Identify Manufacture) command and it will respond with “Gateway TelePath” followed by the version number and the memory checksum.

Noise and Grounding: The TelePath does require a clean ground (talking about your 110 outlet) to operate effectively. This is due in part to the type of telephone line interface module that is used in order to meet FCC, UL and foreign requirements. One of our Beta testers was having all sorts of headaches until he found that his ground was at 80 VRMS. This should not be an issue, since it is a really bad (not to mention possibly illegal) idea to operate electronic equipment without a proper ground. As far as phone line noise is concerned, we are all familiar with the wide range of telephone lines that you may encounter at any given time; but most “line noise” is probably related to the grounding issue mentioned earlier. Remember, Ma Bell never expected anyone to push 14,400 bps through their phone system, so it shouldn’t be surprising to run into problems occasionally. There WILL be phone lines or Central Offices that have too much noise for the modem to handle. This won’t happen often, but no one can guarantee 100% connection 100% of the time. We will guarantee that if your PBX uses ADPCM you WILL have serious problems with ANY modem.

Approvals: The TelePath, when installed in an approved Gateway system, is UL listed and meets FCC parts 15 and 68. The Canadian DOC and CSA approval process is moving forward rapidly. European approvals are pending, but we have absolutely no idea how long the process will take (so please, don’t ask).

16C550: The C19 processor emulates a 16C450 UART and is NOT 16C550 compatible. Why? Simple — the C19 was around before the 16C550 became such a hot item. (A rough and incomplete summary for those that care: the 16C450 UART does not have buffers between it and the host computer; the 16C550 does. This cuts down on the number of interrupts required.) This does not prevent the TelePath from multi- tasking. It will slow down your other applications more than a 16C550 would, but things should still work. However, if you’re running a 80386SX, you’re going to notice the difference. We have downloaded and faxed in the background with great success on our high speed 386DX and 486 machines.

Software: None of the TelePath issues are directly related to the software (WinFax Pro). The engineers at Delrina (the guys who wrote WinFax) were extremely helpful during the debug and troubleshooting stage of this endeavor. They were able to modify one of the WinFax files to ‘work around’ the firmware bug. This file is available on the Gateway BBS at (605) 232-2224 and is named “mod.exe.” The user should just copy it over his existing “mod.exe” file. More details are given in both the “Gory details” and “The Fix” sections later.

Supported Protocols: OK, the ad did say “try and find one we don’t support” and I admit I took a little marketing license when I wrote that. True to form, our customers found one: Bell 208B. This is a synchronous only mode that is used primarily on leased lines. While it has been in use for years, it has not gained the acceptance (outside the US government) that the CCITT standards have. There has been a lot questions about V.32, V.32bis, V.42, V.42bis and HST. HST is a proprietary format that can be sold only by US Robotics. No V.32bis modem, (other than a USR Dual standard), can talk to a HST modem at greater than 2400bps.

BBS: Our BBS continues to use US Robotics Dual standard modems simply because many of our customers bought HST modems before we offered a 14,400 card. Remember this: HST does not equal V.32bis! See “Supported Protocols.”

Gory details for the true modem buffs, (you guys who have nothing else to do on a Friday night but talk to each other on networks): One of the many parameters that the transmitting fax requires is “ST” (Scan Time per line). This is returned to it in response to the +FDIS command as an integer value between 0 and 7, translated into milliseconds and passed on to the host software. The TelePath firmware would sometimes mis-translate this value. Winfax, believing that it was communicating with a slower fax machine, would pad its data. Some fax machines would politely ignore these extra padding characters; some would get quite upset about it and disconnect. This was also dependent on whether the modem was in High or Low resolution. In addition, software packages that ran in Class 1 would be affected differently since the software was responsible for the “ST” translations.

The Fix: At Gateway’s request, Delrina, (the guys who wrote WinFax), modified the code so it would transmit in Class 1 and would receive in Class 2. This special version is available only from Gateway’s BBS. All this is transparent to the user since the software always initializes the modem each time it sends or receives anyway.

Class 1 Vs Class 2: The main distinction between Class 1 and Class 2 involves where the negotiation is handled. In Class 1, the host computer handles all this; while in Class 2, these tasks are delegated to the embedded processor on the fax card. Either class can send to either, and neither the transmitting nor the receiving fax knows what class is at the other end. This term is somewhat irrelevant to a stand-alone fax machine since it doesn’t generally have both an embedded controller and a microprocessor.

The Great Gateway TelePath Cover-Up: It has been rumored that all Gateway employees have been carefully briefed regarding just what has happened with the TelePath and how to cover-up the details with complicated, well choreographed stories. Get real, folks! Gateway didn’t become the largest direct retailer of computers by feeding anyone bull. But thanks for giving us credit for being that organized. The truth is that all our resources were being used to figure out what the problem was, what the fix was and how to explain it to Ted and to the public.

Summary: Telecommunications is a nebulous, constantly- expanding and somewhat confusing art form. Our rocky start will be filed under the heading “Lessons Learned” and the sleepless nights and 70 hour work weeks forgotten (I hope). What must be remembered is that the goal of the TelePath is to provide an inexpensive, high performance fax/modem — one that would fulfill the communication needs of the majority of our customers. This has been accomplished. Maybe soon I can move on to another project where I don’t have to listen to that irritating negotiation sequence anymore. I have been told that some people actually “play” with modems as a hobby (could that be true?).

“Gateway 2000 believes the Telepath is a fundamentally sound product. We successfully Beta tested the Telepath at sites nationwide but did not fully anticipate the wide variety of telephone and electrical environments. Telephone and Electrical conditions differ widely between user sites and naturally fluctuate within acceptable norms; unfortunately, these fluctuations and their interaction has caused the Telepath to be less than fully functional in some situations.”

“Gateway 2000 is doing a modification to the Telepath. We expect to begin shipping the modified Telepath by the middle of June.”

“The one year warranty on all Telepaths will not begin until 30 days following shipment of the modified Telepath. This will not affect the warranty on your Gateway PC which is one year from the date of delivery of the PC.”

“We appreciate your patience, apologize for any inconvenience and are working hard to satisfy you. Customer satisfaction is our number one priority. We will keep you informed on this matter.”

-Gateway 2000-