How many 64 kbit/s service time slots can one E1 provide under the PCM30/32 frame structure?

One E1 has a bit rate of 2.048 Mbit/s and is divided into 32 time slots under the ITU-T G.704 PCM30/32 frame structure, of which 30 are 64 kbit/s service time slots while the remaining time slots are used for frame alignment and channel-associated signaling. The telephone, magneto, EM audio and serial port data services of the IDM MINI8 are multiplexed and share these 30 time slots: a voice channel is encoded at 64 kbit/s in accordance with A-law in ITU-T G.711 and occupies one 64 kbit/s time slot, while serial port data at a lower rate can be multiplexed into low-speed time slots within the same E1. The various services are independent of one another in their time slots, and a change to one service does not affect the other services. During capacity expansion, it is necessary to check both whether the slots are sufficient and the number of time slots remaining in the E1.