On 10/26/2018 04:00 PM, Carlos E. R. wrote:
They were split into channels which were sent their different ways inside the switch (exchange). The problem were the channels, because they had different capacities: 64 Kbps on the E1 and 56 kbps on the T1, IIRC. I think there was a software conversion done, but I never saw it. A further consideration was the µ-law algorithm, different each side of the Atlantic (A-law my side). I did not need to know ;-)
That 56 Kbps was the reason why modems had that top speed at that side of the Atlantic. And ISDN too. Linux had to know that (lame excuse, I know).
That would depend on how signalling was done. The old way was "robbed bit" signalling, where the 8th bit was used for signalling. With out of band signalling, as used in ISDN PRI an BRI, a dedicated channel was used for signalling, so that PRI ISDN would have 23 64 Kb "bearer" channels for data and a single 64 Kb "data" channel for signalling. BRI ISDN used 2 64 Kb bearer channels and 1 16 Kb data channel. With separate bearer and data channels, conversion between T1 & E1 was much easier, as you were dealing strictly with 64 Kb channels. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org