wtm@neoucom.UUCP (Bill Mayhew) (08/01/88)
Hi, Everex is more or less a distributor of products that other companies make to Everex's specifications. I presume that likely not all Evercom 24 modems are made by the same generic Taiwan electronics company. This would explain why some net users love them while other net denizens despise them. We have something like a dozen Evercom 24s in operation here. Several have failed. When they are working they seem pretty good. One thing I miss is having MNP protocol in them. Our campus is literally out in the middle of a corn field, thus the phone lines aren't too quiet. Noise is even more noticable at 2400 bps than 1200, and error correction is an important need for us. I did a post mortem on one of the failed Evercoms before sending it back for in-warranty repair. It was a peculiar failure, as the modem would pass its digital and analog loopback tests just fine, but it would not send any characters over the phone line. I discovered that a CMOS 4053 analog switch had blown out in one of its positions that connected the transmitter output to the phone line audio driver. The Evercom seems to have pretty decent looking protection, having both a gas discharge tube and an MOV. Some of the no-name import modems that I've examined scrimp in the line surge department. One particularly ratty example I saw used only a pair of 1N4002 diodes... apparently hoping that any surge would exceed the PRV rating of the diode and be shunted out. I presume that the failure of the Evercom modem was a purely random event due to infant mortality failure in the IC. If anything, this perhaps indicates that the manufacturer didn't adequately burn-in test the modem before shipping. --Bill