Hello,

I recently received my first two US Robotics modems for my Mystic BBS. Unfortunately, the first one was defective, but the seller refunded me.

The second modem is brand new, yet neither of them responds to AT commands. However, the new one does dial out and can synchronize with a BBS. The issue is that it doesn't respond to any AT commands sent to it. This is causing a significant problem with Windows because, without proper responses to AT commands like "OK" or "ERROR," Windows fails to recognize the modem. This also affects SEXYZ, as it expects the modem to acknowledge its commands.

I suspect there's something I'm missing or haven't done correctly. These are US Robotics 5686 modems, which are standard serial modems. I've tested them on several serial ports across multiple computers, including the built-in ports on the motherboard and special RS232 serial cards.

Does anyone know how to resolve this issue?

VA2RFC BBS Les M‚chins, Qu‚bec Canada
SysOp: rmurray PhoneNet: 1000040 (Modem)
Telnet: va2rfcbbs.photorm.net:23 FsxNet: 21:1/235 FidoNet: 1:229/114

--- Mystic BBS v1.12 A48 (Windows/64)
* Origin: VA2RFC BBS (21:1/235)

Re: USR 5686 no replay at AT command
By: rmurray to All on Wed Aug 21 2024 11:05 pm

I recently received my first two US Robotics modems for my Mystic BBS. Unfortunately, the first one was defective, but the seller refunded me.

The second modem is brand new, yet neither of them responds to AT commands. However, the new one does dial out and can synchronize with a BBS. The issue is that it doesn't respond to any AT commands sent to it.

In order to dial a phone number, you need to use the ATDT command, so it sounds like it at least responds to that AT command?

Nightfox
--- SBBSecho 3.20-Linux
* Origin: Digital Distortion: digdist.synchro.net (21:1/137)

In order to dial a phone number, you need to use the ATDT command, so it sounds like it at least responds to that AT command?

Nightfox

The modem accepts all commands like ATDT without any issues. However, when sending basic commands like AT, ATA, ATE1, or AT&F, which should normally respond with an "OK," there's no response at all. Although the commands themselves are executed, the expected "OK" response is missing. Consequently, SEXY isn't working because it requires feedback from commands like AT&F, ATS0=1, or ATS0=0, but since there's no response, the issue persists with both modems.

This indicates that the problem likely isn't with the modem itself but rather with the computer's configuration, possibly related to incorrect DIP switch settings. I've also tried this on Linux with both modems, and the same issue occurs.

VA2RFC BBS Les M‚chins, Qu‚bec Canada
SysOp: rmurray PhoneNet: 1000040 (Modem)
Telnet: va2rfcbbs.photorm.net:23 FsxNet: 21:1/235 FidoNet: 1:229/114

--- Mystic BBS v1.12 A48 (Windows/64)
* Origin: VA2RFC BBS (21:1/235)

On Thu, 22 Aug 2024 00:19:10 -0400
"rmurray" (21:1/235) <rmurray@f235.n1.z21.fidonet> wrote:

In order to dial a phone number, you need to use the ATDT
command, so it sounds like it at least responds to that AT
command?

Nightfox

The modem accepts all commands like ATDT without any issues. However,
when sending basic commands like AT, ATA, ATE1, or AT&F, which should normally respond with an "OK," there's no response at all. Although
the commands themselves are executed, the expected "OK" response is
missing. Consequently, SEXY isn't working because it requires
feedback from commands like AT&F, ATS0=1, or ATS0=0, but since
there's no response, the issue persists with both modems.

This indicates that the problem likely isn't with the modem itself
but rather with the computer's configuration, possibly related to
incorrect DIP switch settings. I've also tried this on Linux with
both modems, and the same issue occurs.

VA2RFC BBS Les Méchins, Québec Canada
SysOp: rmurray PhoneNet: 1000040 (Modem)
Telnet: va2rfcbbs.photorm.net:23 FsxNet: 21:1/235 FidoNet:
1:229/114

--- Mystic BBS v1.12 A48 (Windows/64)
* Origin: VA2RFC BBS (21:1/235)

If it's not, try flipping switch 4 into the UP position.
--
End Of The Line BBS - Plano, TX
telnet endofthelinebbs.com 23
--- SBBSecho 3.20-Linux
* Origin: End Of The Line BBS - endofthelinebbs.com (21:2/101)

If it's not, try flipping switch 4 into the UP position.
--

No difference... :(

VA2RFC BBS Les M‚chins, Qu‚bec Canada
SysOp: rmurray PhoneNet: 1000040 (Modem)
Telnet: va2rfcbbs.photorm.net:23 FsxNet: 21:1/235 FidoNet: 1:229/114

--- Mystic BBS v1.12 A48 (Windows/64)
* Origin: VA2RFC BBS (21:1/235)

On Thu, 22 Aug 2024 13:13:15 -0400
"rmurray" (21:1/235) <rmurray@f235.n1.z21.fidonet> wrote:

If it's not, try flipping switch 4 into the UP position.
--

No difference... :(

VA2RFC BBS Les Méchins, Québec Canada
SysOp: rmurray PhoneNet: 1000040 (Modem)
Telnet: va2rfcbbs.photorm.net:23 FsxNet: 21:1/235 FidoNet:
1:229/114

--- Mystic BBS v1.12 A48 (Windows/64)
* Origin: VA2RFC BBS (21:1/235)

Are you on Winderz or Linux or something else? Hmm, Crapintosh since
you're using Phonenet? :)
--
End Of The Line BBS - Plano, TX
telnet endofthelinebbs.com 23
--- SBBSecho 3.20-Linux
* Origin: End Of The Line BBS - endofthelinebbs.com (21:2/101)

Are you on Winderz or Linux or something else?

My BBS is under WinSlow 10 Pro x64. :)

VA2RFC BBS Les M‚chins, Qu‚bec Canada
SysOp: rmurray PhoneNet: 1000040 (Modem)
Telnet: va2rfcbbs.photorm.net:23 FsxNet: 21:1/235 FidoNet: 1:229/114

--- Mystic BBS v1.12 A48 (Windows/64)
* Origin: VA2RFC BBS (21:1/235)

In them good 'ol days you'd think the thing was a dud, or you got t he port speed wrong... However if as already mentiond it ATDTs then thats not going to be it.

Scratching my head, I recall some modems have an option for numerial response vs an OK, or CONNET XXXXX, and some having a quiet mode, with no response. But you'd have to check the AT set specific to your modem. They were kind of non standard.

ST

--- Mystic BBS v1.12 A48 (Linux/64)
* Origin: Storm BBS (21:2/108)