Dial Up Modem Sounds, 56K Edition
This is a follow-up to the earlier modem sounds video here: • Dial Up Modem Sounds, from 300 bps to 56K
The sound of 56K for various modem models and standards. Prior to V.90 there were competing x2 and K56 Flex standards, which are included here. Even when V.90 was official though, different models of modems tended to sound different from one another when connecting. This is the result of part of the V.90 spec called the Digital Impairment Learning sequence (DIL). The analog (client) modem asks the digital (ISP) modem to send a set of symbols (sounds). When the analog modem receives those symbols, it can compare the sound it asked for and the sound it received to determine how it was degraded by how the digital signal was handled along the path from the ISP, and then adjust the connection speed to compensate. The digital signal might be affected by things like Robbed Bit Signalling and digital pads.
The interesting thing is that the V.90 spec doesn't actually specify what the DIL sounds should be, just that the digital modem should send whatever the analog modem asks for. The result is that it can sound quite different for different client modems. This video is just a sample of a few different modem models connecting using V.90.
Server Specs:
AMD K6-2 @ 350MHz
512MB SDRAM
16GB SD Card w/ SD/IDE Adapter
10Mbps 3COM 3C509 ISA Ethernet Adapter
US Robotics Courier I-Modem (x2 and V.90 support)
Patton Dialfire 2977/B4/U (K56 Flex and V.90 support)
Dialogic Diva 4BRI-8M PCI v2 (V.90 support)
Windows Server 2003R2
Laptop #1 Specs:
Toshiba Tecra 500CDT
Intel Pentium @ 120MHz
144MB EDO RAM
1.2GB IDE HDD
12.1" 800x600 Active Matrix TFT LCD
Windows 98SE
Laptop #2 Specs:
Compaq Armada M300
Intel Pentium II @ 333MHz
128MB SDRAM
6GB IDE HDD
11.3" 800x600 Active Matrix TFT LCD
Windows 2000 Professional
Laptop #3 Specs:
Lenovo Thinkpad X1 Carbon G9
Intel Core i7-1185G7
32GB LPDDR4-4266
1TB Western Digital SN850 SSD
14" 1920x1200 IPS LCD
Windows 2000 Professional (in a VirtualBox VM)
Teltone ILS-2000 ISDN Simulator
Dialogic DIVA T/A ISDN terminal (used for Analog/Digital connection)
0:00 Intro
0:04 x2
0:30 K56 Flex
1:05 US Robotics V.90
1:36 Zoom V.90
2:11 Hayes V.90
2:40 Intel V.90
3:11 Creative Labs V.90
3:45 Xircom V.90
4:25 Lucent Softmodem V.90
4:59 Agere USB Softmodem V.90
5:37 Frank the Snake